141 - Neil Bell - The best pollinator shrubs and trees


Speaker 1: From the Oregon State University Extension Service, this is Pollination, a podcast that tells the stories of researchers, land managers, and concerned citizens making bold strides to improve the health of pollinators. I'm your host, Dr. Adoni Melopoulos, assistant professor in pollinator health in the department of horticulture. It's National Pollinator Week this week and it's a very strange one. Many of you, my listeners are typically out at farmers markets, at plant clinics, and nurseries, talking to the public about steps they can take to help pollinators.

But unfortunately, that's all kind of gone off the rails or kind of. If you go to a website like Pollinator Partnership, you'll see that there's a map of all sorts of activities that are happening virtually in your area. So please check that website out if you don't know what you're going to be doing this week.

But if you are in Oregon, you're in luck. We've got a great event right Monday at noon that's going to feature some of the powerhouses in the OSU Extension Master Gardener Program. We're going to answer questions, any question you can possibly dream of when it comes to gardening for pollinators. And the occasion for this as well is the release of two new publications from OSU Extension. The first, Enhancing Urban and Suburban Landscapes to Protect Pollinators, a new 41-page manual for gardening for pollinators in the state, but also Trees and Shrubs for Fall and Winter Bloom.

This a great publication, we can get some great bloom here into the late winter that bumblebees and honeybees, but also our hummingbirds will visit. Today's guest is an author of both those publications. He's also going to be on the panel on Monday.

And I also have to say he has been an inspiration and mentor to me as a young faculty member here at OSU. It's Neal Bell. Neal oversees the Master Gardener programs in Marion and Polk County. He does a lot of research on shrubs, including California lilac, and cystus. You'll hear about a lot of that in the show because I've brought him on the show to talk about some of the top pollinator shrubs and trees for Western Oregon. Please register for the webinar by typing buzzing and beautiful designing pollinator gardens with OSU Extension on the OSU Extension website.

You'll be directed to a registration button. And I also want to ask, we are doing a survey for the show. The survey this summer, which I'm going to be plugging, is really important to me in getting a sense of who you are what you're listening to, and what you're learning. But beyond that, you can also win a hard-to-find Oregon Bee Project Ball Cap.

I'm going to give 10 of these hats away to people who answer the survey. So don't delay. Type the following into your browser or you can find this in the show notes. Type BEV.ES. So BEVs. BEV.ES. Backslash for lowercase J. Capital S. So again, BEV.ES. Backslash for lowercase J, uppercase S. And fill out the survey.

It doesn't take very long. So without further ado, here's Neal Bell. Okay, I'm here with Neal Bell. I'm so excited. Hi Neal.

Welcome to Pollination, finally. Thank you, Antoni. Good to be here. You know, I have to admit one of the turning points in my career was getting a slide deck from you.

You generously gave me back when I started at OSU. And that slide deck actually is sort of the backbone of a new publication that we've just released on Urban and Suburban Pollinators.

Speaker 2: Yes, and it was a pleasure to give it to you as well because you have taken that modest PowerPoint presentation and turned it into a fabulous publication, an all-encompassing publication, which there was no way I was going to pull off. So good for you.

Speaker 1: Well, today I think we're going to focus on one aspect that is in that publication, but also a brand new publication that you put out this winter blooming Shrubs and Trees. And that is Shrubs and Trees. They're kind of oftentimes people don't think about Shrubs and Trees. We think about perennials or maybe pollinator meadows, but Shrubs and Trees are kind of an important part of, I would imagine, any kind of pollinator garden or landscape.

Speaker 2: Sure. I mean, generally speaking, compared to annuals of perennials, physically they're larger, which needs to be accounted for. When we talk about maintenance later on, I'll reiterate that point. But of course, particularly in the case of Shrubs, they vary greatly in size and just offer some flexibility and permanence in the landscape, particularly if they're evergreen. So there's some flexibility there both for design and also, of course, as a source of nectar and pollen for an array of pollinators.

Speaker 1: So yeah. Well, I did want to go in. I wanted to pick your brain. I know one thing I remember about that slideshow that was remarkable is you had a picture of almost every shrub and plant in a garden that attracted bees in Oregon. You have a massive kind of observation set of watching bees on shrubs and trees and annuals and perennials. And so I wanted to go through and just kind of help have you sort of walk us through some thinking about West of the Cascades, some good shrubs for different parts of the season. So just beginning with spring, what are some of the, if you were to pick five, if I was a put, you know, sort of say, I need you to kind of narrow it down to five, what are five, you know, go to, have to shrubs West of the Cascades for pollinators.

Speaker 2: For spring, you mean? Yeah. Well, you know, the thing about spring is that we have an abundance of native shrubbery and trees, which are obviously by definition perfect for native pollinators as well as non-native ones like honeybees. So the array of willows that we have that usually start blooming in March, osoberry, possibly one of the earliest woodie modest, modestly sized woodie shrubs that we have this year actually started to bloom in late February.

So it was kind of an early year. And then of course there's flowering current as well as Oregon grape, all of which are, you know, ubiquitous and very colorful native shrubs. One we were just chatting about that is epic in size. It's also great in sort of a tree form or large shrub, depending on how it's pruned, is big leaf maple. And maples in general are incredibly attractive to pollinators, both the native ones like big leaf maple as well as non-native ones. So to the point where you can hear the plants, you know, there's so many pollinators on them. It's just a great plant for pollinators for the early part of spring. And then there are others like thimbleberry and bitter cherry and so forth that are also native as well. So especially in spring, the native flora is really rich in flowering trees and shrubs. Okay.

Speaker 1: Let's go over some of those. One of which, you know, we had a previous podcast, like I was thinking about people who have mason bees. You know, things like Oregon grape and maple are just proven choices for propagating mason bees in your backyard.

But one that came up, we had a podcast with Lila Westreich up in Seattle. And she noticed that the vast proportion of pollen in a lot of these mason bee nests were willow. But it strikes me willow is kind of a difficult plant to put in because they're so darn big. Any tips on willows? Are there small willows that you can get or how does one work with willows in their garden?

Speaker 2: You know, that is a good question. The ones that I see, the imagery that I have a willow, I don't grow any willows other than one which is just naturally occurring in our garden. We have acreage in Polk County, west of Monmouth. So we have a larger area to accommodate the garden, but we also have native trees and shrubs on the property. One of which, oddly enough, is a willow. And I say oddly because we're on a ridge, but there's clearly a spring on the ridge which is allowing thimbleberry and this willow to grow and thrive even in where it's not near a watercourse, it's near a spring. Well, anyway, this willow is literally 40 feet tall.

It's huge. And I think that one of the limiting considerations for willows in a garden situation is just their sheer size, which isn't an issue for things like flowering currant or Oregon grape. Not only are they modest-sized shrubs to begin with, but there are also dwarf forms available as well. And I'm sure that there must be dwarf forms of some of our native willows as well, but I have to be honest, I'm not really familiar with those. In general, I think of them as being fairly large plants.

Yeah, for sure. Beautiful and bloom, and amongst the earliest to bloom, but also have that issue of size. In general, small to modest size plants are going to be more adaptable to smaller gardens these days.

Speaker 1: Are any of these plants, I guess since a lot of them are native, they're probably mostly water-wise. It's like we're looking at plants here that you need to water to establish, but these are probably all all these spring plants since their natives are probably fairly easy on water. Is that is that the case?

Speaker 2: we grow all the ones that I mentioned and none of them are our garden in general is not irrigated, whether it is consistent native stuff or the nonnative things we planted. But no, the beauty of them is that they are assuming that the native plant is not a riparian plant.

Then by definition, they will get by on whatever falls out of the sky. So yeah, they're summer-adapted to summer drought. So in some cases will even tolerate a little bit of shade. You know, I think in general any of the native plants that we discussed will be happier in full sun. That's the thing about and when you plant them in partial shade or full shade, then what what actually suffers is the flowering and growth of the plant. Since you know the flowers are what are producing the pollen and nectar full sun is definitely going to be better, but they will not require supplemental water in the summer.

Speaker 1: Okay, let's move on out of sort of the early spring into sort of mid-spring or early summer and what are some of your favorite pollinator plants there?

Speaker 2: If you can accommodate them and deal with the fact that they sucker, which they do with wild abandon, the native roses are great. You know, the suckering can be a good thing if it's a sort of informal area of the garden, but if you're thinking hybrid tea rose in a nice tight little growth habit, that's not our native roses.

But they're beautiful, they're fragrant, and obviously attractive as other roses are to pollinators. Cianotus, the native Cianotus that we have, Cianotus Sanguinius is a huge plant. Ceanothus cuneatus is a buck brush, which is a white flowering evergreen shrub. Those and other Cianotus non-native ones are very attractive in most cases to a wide array of pollinators. And then of course there's Ocean Spray, which I think might be my favorite native shrub, which is coming into bloom about now.

June is kind of the month for Ocean Spray. So those are really attractive shrubs in bloom and then also really attractive to pollinators. If you do have a little bit of a damper area or can supply a little bit of supplemental irrigation, then one of our most common native spirea, spirea dualistic, or hardhack as it's sometimes called, is kind of a suckering deciduous shrub with these spikes of purple flowers. So I mean if you're out and about in the valleys, you'll see these in bloom probably about now and they generally are in a little bit wetter areas, I guess you would say, so they're happier in those kinds of environments. And then the other one that comes to mind, which actually is maybe one of the longest bloom periods of a native shrub, is Snowberry, which starts blooming now or even earlier than this. And you might even find flowers on it in August, so that's kind of like a low suckering, almost like a ground cover type plant. And if you see it in bloom, it's almost comical. Bumblebees can't get enough.

Speaker 1: I know, but there's not a lot of flowers.

Speaker 2: No, I know. So the bumblebee will literally be about 10 times as big as the flower that it's hanging off of. So it just shows how determined they are. But then the fruit form, they're not edible, but presumably, the birds they are. And so yeah, as a compliment, if you like, to some of the other plants, it makes a good sort of low ground cover to work itself in and around the other shrubs that you're using. So I mean, honestly, just using what's native to Willamette Valley, one can put together a landscape that provides just shrubs and trees blooming from late February through probably the middle of August or so, or maybe even a little later. Quite a long period.

Speaker 1: Well, let's talk about some of those shrubs in more detail now. Cianothus, I remember you had done a large or were involved with a large trial at Oregon Gardens with different Cianothus. And I know there's a wide range of forms, you know, outside of the OSU Horticulture Department. There's in the parking lot, there is even a ground cover form. Tell us a little bit about Cianothus and some of the tricks around it.

Speaker 2: Right, so native North American shrubs, there's Cianothus, we think primarily of Cianothus as being native to the West Coast, but there are also deciduous or semi-deciduous species native to the Midwest and East Coast as well. And so some hybridization has gone on between those and the evergreen forms on the West Coast. So we've got this rich array of Cianothus which vary in growth habit from ground covers and the most commonly used ground cover that is native to California, Cianothus gloriosus. So that will form an evergreen mat about 18 inches tall, I would say, and probably about five or six feet wide. So they're very vigorous but also very flat. Nitrogen-fixing shrubs mean they will tolerate poorer than average soil, I guess you would say, as long as the drainage is good without requiring supplemental nitrogen fertilizer after it's established, which is kind of a cool thing, right?

I mean that's another beneficial attribute of those. And then the bloom time varies all over the board for Ceanothus from, I would say, probably late March to about the end of July, just depending on which one you choose. Because some bloom on old wood like the evergreen forms and then some of them bloom on new wood like some of the deciduous and hybrid forms.

So the bloom time is very long. The growth habit, as I mentioned, can be flat. I took a picture one time down around climate falls of Cianothus prostratus, which as the name suggests is just a flat little mat. It's only a few inches tall. Ceanothus gloriaus is a bit taller than that. And then you get into the sort of rounded shrubby forms like Ceanothus dillelianus. There are various cultivars of that.

It's a hybrid form like Topaz and Guard of Versailles. So those are form shrubs that are about five feet by six feet or so in size. And then there's a lot of them that are just gigantic.

And so you need this space. And one of the most pitiful things I see is when somebody takes one of the most commonly grown evergreen forms of Cianothus, this is one called Victoria. And it's a big shrub.

It's like eight feet tall by eight feet wide or bigger. And I've seen it stuffed into places where it just did not belong. And that's the cardinal sin of pruning, right, is putting an eight-foot tall by eight-foot wide shrub into a three-foot tall by three-foot wide place. And then you're into this constant need for pruning the plant, which is usually not good for the plant's appearance or health. So yeah, Cianothus does vary in size greatly.

And so I would encourage people to choose the one that works for them based on available space. And when you give it enough space, they're glorious plants. And they're all to varying degrees attractive to a wide range of pollinators. And like I said, there's a couple of native ones. The native evergreen one to the Willamette Valley is Cianothus cuneatus, which has white flowers, and is very often seen, but is available in native plant nurseries. Ceanothus cuneatus is another one, and it tends to be one of the really big ones.

Speaker 1: Are they mostly available? That brings up a great question. Is the variety available in nurseries, or is there really only a couple of varieties that you can find without a lot of effort?

Speaker 2: No, I think the thing that we're blessed with here in the valley is a lot of specialty retail or mail-order nurseries, which will offer some of those rarities. So just by searching around, yeah, I mean, there are some standards, right? Like Ceanothus gloriosis, that's the standard ground cover. Cianothus Victoria, that's the standard big Cianothus. But there are all these other hybrids and cultivars of both native ones and non-native ones from California, which are out there, and offer a range of sizes and bloom time. So like I said, they range in size all the way from that little ground cover I mentioned, Cianothus prostratus, up to enormous plants that are much bigger even than Victoria. So just think of the available space and choose the plant accordingly.

Speaker 1: Well, thinking about space and size, I also love Ocean Spray, and we featured it in the Oregon Bee Project. We have this kind of like shrub of the wheat kind of thing. But it can be pretty big.

Speaker 2: Oh, yes, I've seen them where they were 12 feet tall and 15 feet wide, you know, just big arching shrubs. And I think part of the reason is especially to see them in a park or the wild or whatever, they're never pruned, they're never managed.

So they just get big and lanky with time. But I think if you were to manage it in a garden situation, you could, by judicious and appropriate pruning, keep it to about eight feet tall, which is about how high they want to be, and maybe that or not even that wide. And what you'd have is a nice vase-shaped shrub, which is typical of a lot of sort of cane-growing plants. And that's a very handy growth habit because it's more vertical than it is wide. So then you could work in things around the base of it, which wouldn't be shaded for the most part by the Ocean Spray. So you can kind of utilize the growth habit of shrubs in a way which is complementary to, you know, more mound sort of forming plants or lower growing things without impeding the growth of either one.

So yeah, I agree. I've seen gigantic Ocean Spray specimens, but I've planted several along a new planting on our driveway, and I intend to keep them kind of as I described, mainly because I've probably overplanted the whole bed anyway, and I need to keep room for all the other plants that are nearby.

Speaker 1: Well, one shrub to a tree that I didn't hear you mention that I know you know a lot about are manzanitas. Tell us a little bit about manzanitas. They're so beautiful.

Speaker 2: Yeah, they are. We had an evaluation of manzanitas up in Aurora at the North Melamed Research and Extension Center for seven years. And again, that's a Western North American shrub. The best-known manzanita actually is linolenic, which is in the same family, Archastaphalos, with the same gene as I should say. Archastaphalos and it's got the widest distribution of any.

It's circumpolar, so Northern North America and Northern Asia. But in addition to that, which is one which most people would be familiar with as a diminutive ground cover, kind of like the sea in the oath there's a manzanita for every situation, assuming that it's full sun and reasonably well-drained, especially in the Willamette Valley. And they just range greatly in terms of size from little ground covers to large tree-like shrubs. And the thing about manzanitas, is they're all evergreen shrubs. Many of them, especially the larger shrub form of incredible bark. And then there's the blooms. And so what we found with our trial was the earliest of them start blooming after Thanksgiving. That was Archastaphalos refugioensis. The flowers on that turned out to not be particularly hardy and it's a California species.

So I mean, I wouldn't suggest that one. But there are others like one called sentinel, which started blooming in December and into January. So January was really its prime bloom period. So depending on the cultivar, you could have one in bloom at a time of the year when nothing native is out there. And if it was warm enough, then you would see pollinators out there in January and February working those flowers. And the one thing you can be guaranteed is if you have to overwinter and as hummingbirds, they will love you for having those winter blooming forms of manzanita in the garden. And sentinel was an evergreen shrub that would reach about, you know, eight feet by eight feet.

So again, it needs space, but very reliable. I never saw winter injury other than minor winter injury to the flowers or the plant. I had a pink bloom. So I mean, it was just a real winter for if you could only plant one and you were looking for that niche for the winter, that would be a great choice. There are others like Siskiu Pink, which is another upright shrub form, which is about the same size or maybe a bit bigger, that also has pink blooms around the same time of year. But depending on the manzanita you choose, you could have something that continues to bloom through the end of April just by species or cultivar selection. Very hardy, very unique, and super drought tolerant plants never apply a drop of water to a manzanita. Fantastic.

Speaker 1: Well, we'll come to winter in just a second, but let's deal with this kind of like full summer going into fall. We're getting pretty dry in the valley. What kind of, what are some of the shrubs and trees that we want to look at?

Speaker 2: So the sea and earth, as I mentioned, and again, there's a large number of those. So those are good choices, which will carry you into the middle of summer. And if you're willing to consider non-native stuff, then, I mean, rosemary is a great pollinator plant. You'll find, especially honey bees, I mean, that's not surprising because these are of Mediterranean origin and of course, European honey bees are European in origin.

They are very attractive to any cultivar of rosemary. So that's one species. But many, many different cultivars out there. The bloom time varies greatly as well, actually from winter into mid-spring. Then there's lavender, which, again, there's a number of different species available. Spanish lavender is generally the earliest one to bloom. But later on, you get the other species and hybrid forms, which will, again, with cultivar selection, that's what it really all comes down to, carry you through the middle to the end of August.

So those are good selections. Things like Shrubbi St. John's wort, which is Hypericum. Those have these bright yellow flowers that bloom in mid-summer. So you get a lot of bang for your buck out of those. And then later on, things like sages, and salvia. There are a lot of different salvias.

I mean we've got salvia and bloom now in our garden. And a lot of those are sub-shrubs, I guess you would say. So not quite a full woody shrub, not a perennial either. They're actually a woody plant. But depending again on which species and which cultivar you select, you can have this array of blooms in your garden. And again, that would be hummingbirds and pollinators from, I guess, the end of May through the hard frost.

Speaker 1: You know if I could just stop you for a second. That's something I never think about during the summer. I always think about the winter for hummingbirds. But I guess they're still around and they're still pump and nectar. I guess my attention turns to the insects as soon as they're out in force.

Speaker 2: But we do need plants for hummingbirds all year round. Yeah, yeah. So for the, yeah, easily. There's essentially the same array or similar array of plants that would keep the pollinators happy and will also, in a lot of cases, keep the hummingbirds happy as well. And that sages are, salvias are a great example of that. You'll find both hummingbirds and pollinators attracted to those. So, yeah, I mean others like bluebeard, and karyopterus, those are super attractive to various pollinators. And then they're later blooming. We have a couple and actually, I grow them in pots because they like a little more water than I typically give to most of our garden. So I grow them in pots on our patio and they aren't in bloom yet.

So their time is mid-July to say the end of August or September. And then the other one which you do see in landscapes which is pretty tough is Russian sage. So, I mean here, again, we're getting into the time of year where the native woody flora is kind of petering out or probably ending with snowberry.

And so we're looking for non-native stuff to kind of take up the slack, so to speak. So Russian sage will be at its peak in late August and September along with the bluebeard or karyopterus. And then, of course, the sages as well. And then the other one that bears mentioning is chastity which is a Vitex agnus castus. And that's a deciduous shrub.

I call it a sub-shrub just because it blooms on new wood. And it's not in control. But left to its own devices, chastity will get to be a very, very large plant. But it has these spikes of blue flowers which are at the tips of the shoots and the spikes of blue flowers.

There are also white forms that are about six to eight inches long. Again, this is one of these plants that you will hear before you actually see it because of all the insect activity on it. So that will continue to provide habitat until well into September.

Speaker 1: Well, I know a lot of our beekeepers are interested in trees. Summer is a hard time of year to really feed our honeybees. Do you have any other trees that can give us some... The one that I keep watching is Tillia, which is just about to pop here, at least in Corvallis. Yeah.

Speaker 2: And in fact, they're in bloom. We happened to be sitting under some Tillia in Monmouth just this week. And of course, super fragrant. And it was already in bloom, obviously, because of the fragrance. So that's June. So I'm just thinking of things that are even later in the year. And so there's not that many trees.

And I'm not familiar with their attractiveness, the ones that do bloom in, say, mid-summer. What about Kitalpa? I'm thinking of Kitalpa. Yeah, that's the one I'm thinking of. It's pretty big. And there's a great example down on campus, actually, on Monroe that I've taken pictures of. But what I don't know is how attractive it is to pollinators. But clearly, at that time of the year, it's one of the only trees that is typically found in bloom. That one comes to mind right away. So yeah, we both hit on that name at the same time.

Speaker 1: I guess you need a lot of space for something like that as well.

Speaker 2: Yeah, I'd have to go and have a look at it and actually see. Because most of what I have in terms of suggestions if you like, is based on observations.

I want to see, I want to see the activity in order to say, okay, well, clearly, if they keep coming back to this thing, there's something there that's attracting them. And I just don't know that for Kitalpa. But at the very least, if you plant one of these, you get a very unique, very beautiful flowering tree for mid to late August or even September. And that was one thing I think Bear's mentioning that we actually have observed. We also had a rock rose trial, cysts, and halemium. And I can tell you that they're not all created equal in terms of their attractiveness. Cystus in particular, because they're Mediterranean and origin, rock roses, are very attractive to European honeybees. And I've just noticed big differences in how attractive some species and cultivars are compared to others. So something about some of them is clearly bringing out the pollinators compared to others which look nice in bloom but don't seem to have the same level of attractiveness. Well, it does bring me to

Speaker 1: one of your choices that literally scares me because it's just the diversity is the lavenders. It seems like there are a billion lavenders out there. It seems like most of them attract honeybees and bumblebees. But do you have any sense of, if you were to pick some lavender cultivars, are they all kind of equal when it comes to pollinators?

Speaker 2: I honestly couldn't tell you. What I think I'd tell you is that bumblebees in particular love lavender. And so I've seen them hanging off those stalks of flowers in late July and August. Actually, it's they, those that I most associate with lavender are bumblebees, not so much honeybees or even other native pollinators.

But you're right. I wouldn't even know where to begin with lavender because there are so many cultivars and more arriving daily. But depending again on what you choose, Spanish lavender will start in May and you can just with lavender have a continuous bloom through the end of August, maybe even later than that.

Speaker 1: Okay, well, let's take a quick break and we're going to come back. I want to talk about the winter specifically because we have a new publication on it. And so let's take a quick break. We'll be right back. Okay, we're back. So I wanted to go turn our attention now to the winter because you have a brand new publication out on the OSU extension catalog that focuses on winter-blooming plants. And I know it's been something you've been thinking about for a long time. So walk us through, and it's also a time of year, you know, when a lot of insect pollinators are either finishing, you know, in the late fall, honeybees are getting ready for winter and some of them are finishing their reproduction, or starting the reproduction on the other shoulder part of the season as we get into late winter. So tell us a little bit about some of your top picks.

Speaker 2: Well, you know, the thing about certainly Western Oregon anyway is that it's mild enough, and we have this climate which is so conducive to growing things that bloom year round. So yeah, we have this amazing climate and the diversity of things that will bloom in winter is in fall as well. And again, that time of year when the native, certainly the native woody shrubs aren't blooming is really amazing. So yeah, we put together myself, Heather Stovan, Counter Park in Yammill County, and of course, yourself to provide the pollinator attractiveness information. Because originally I just been thinking of it as a publication for, you know, nice things that one can bloom, one can put in the garden to provide floral interest during the off-season, so to speak. But I've also observed, like I said, for example, on those manzanitas that when the weather is warm enough, you will see pollinators active on them. And I think you can correct me, but I usually think of that temperature being about 58 degrees, which happens a lot, you know, even in January. Every year we seem to get some days where it reaches that threshold around the third week or so of January. You know, and these are there, they're in bloom.

Speaker 1: So it's a good thing. It strikes me that people who fail with mason bees often don't have, when the bees are emerging, something in pretty good bloom by the time the cocoons are hatching, and things like rosemary or, you know, things that are blooming have started blooming in February and really gotten going by the time the mason bee, I think it's a real key part of success. People don't have enough really kind of going in full swing when those mason bees, I think that's what causes them to disperse personally.

Speaker 2: Okay, so I'm not sure exactly what mason bees are attracted to, but let me give you an example of one we haven't talked about, which again is a large evergreen shrub, that will start blooming. Actually, the bloom period of the winter blooming plants varies fairly significantly depending on weather conditions, but if you have space, there's a large relative of our native Oregon grape, it's Mahonia media, and there's a number of different cultivars, but one that we grow is called Charity. And Charity is a spiky, very textural, upright, spreading evergreen shrub to about 10 feet tall and about 8 feet wide, and it's actually pretty easy. They naturally form the sort of big evergreen vase-shaped shrub without really any pruning at all. And on the tips of the shoot in January, they have these spikes of yellow flowers, and hummingbirds are very attracted to these and will battle each other all day long over them, but honeybees in particular, if the weather's warm enough, will swarm over the flowers of these plants. And again, it's one of those plants, you'll hear that activity from a significant distance away. So that's a really good plan that obviously attracts pollinators, because actually, if you look at our publication, not everything that happens to be winter blooming. But so in other words, like Sweetbox, which is a commonly used winter blooming grapefragrant, sort of tall ground cover, and great for that purpose. It blooms, it flowers in the dead of January and smells great. But I don't think I've ever observed any...

Speaker 1: I've never seen one of these. I've watched them on campus. They're hard to miss. They smell so good, but I've never seen a single bee on it.

Speaker 2: Right, neither have I. So I think it's a nice plan for winter and serviceable ground cover, particularly for shade, where it still blooms well. But yeah, I wouldn't recommend it as a plan for sustaining any insect pollinators, just because I haven't observed any activity on there. Another one, that fits the same category, is winter jasmine, which is a non-fragrant, yellow, flowered winter-blooming form of jasmine, which is actually a vine but can be trained into a sort of a standard. And they'll bloom again in late January or early February, but I don't think I've ever seen any pollinators on there.

Manzanita's are different. As I mentioned, you will see bumblebees, you will see honeybees, you will see hummingbirds on the various winter blooming forms of that, and then obviously on into the spring. The other thing I've observed on Manzanita, which is really astonishing, is a photo of what turned out to be a butterfly, a red admiral on the flowers of Manzanita in, I think it was early February. And I would just, what is a butterfly doing out in early February?

Speaker 1: Getting a little bit of juice before going to sleep again, I suppose. I guess.

Speaker 2: So yeah, that one in particular, Mahonia is a really good plan for winter. Another one, which is actually rarely seen, oddly enough, is a relative of the flowering current, which is native to Northern California. And so it's called Chaparral Current, and it's Ribes magnesium.

So that's actually in the publication. And I would say that no plant in that publication has a longer bloom period than Chaparral Current. It typically starts blooming in an early year after Thanksgiving. So in other words, it kind of looks sort of like the flowering current that we're all familiar with. The flowers aren't quite as showy, then they're in the same kind of inflorescence, sort of a dangling cluster of a number of flowers, and they're whitish-pink. So they're not as showy a plant as flowering current, but they start blooming around Thanksgiving or maybe a little later, say the beginning of December. And it will not quit blooming until the end of April. It will have flowers on it that whole time period. So if you're just looking for one plant to carry both your pollinators and your hummingbirds, which will go berserk on this thing as they would on our native flowering current, then the one plant you need is Chaparral Current, Ribes malvasium.

Fantastic. It's completely, one thing you'll have to get accustomed to, it's one of those Mediterranean-type plants, again, from Northern California, which will go dormant in the summer. So when the moisture diminishes in the soil, then it will drop its foliage. So that's one strategy Mediterranean plants will use to tolerate drought.

And that's the one that this plant uses. So it's a collection of sticks in the middle of summer, but then when it starts to rain in the fall, that's when it starts to grow and leaf out. And then again, by the beginning of December, the first blooms will hurt if you're on the plant. Yeah, it's kind of an unusual plant in that regard. Very upright growing. Like other currents, it's a cane-growing shrub. So it has these upright growing shoots to about eight to 10 feet tall, but you can manage the plant to be six to eight feet wide. So if you've got an upright space, again, it's more vertical than it is wide. That's kind of a handy growth habit. But yeah, it's just a really, really long period of bloom.

Speaker 1: When would this be blooming until you said it may start in December?

Speaker 2: Yeah, it'll start to bloom in December. And this year, for instance, it didn't... Its bloom period then overlapped with that of our native flowering current, which we have several of in the garden. Really? By the end of April, it would still have flowers on it.

Speaker 1: That's remarkable. That's amazing. I'm going to plant one tomorrow.

Speaker 2: It's easy from cuttings. I can give you some. Okay, awesome. So the other one, which I think is Bear's mentioning, because I've observed it to be attractive, is another non-native plant. And that is what's called...

It's... The common name is kind of hokey. It's called a spider flower, but it's a gravilia. Gravillia is a native to Australia, for the most part. And they're evergreen shrubs. The one that I have included in the publication, or we included in the publication, is gravilia victoriae, which is a species native to southeastern Australia, which is really the only part of Australia that has a lot of elevation, and therefore some areas which get significant cold, and Tasmania. So those are the areas of that country where we typically are able to find plants hardy enough to grow here. And Gravilia Victoriae is almost completely hardy in the Milan Valley.

Sometimes, you know, if it gets super cold, it'll get some damage. But anyway, it has these red flowers in clusters, which begin blooming again in December. And this is another one of those plants, which has a bloom period almost as long or as long as Chaperalcurrant. So it'll begin blooming in December, and then the blooms will continue to open through at least the end of March or into April.

Wow. So again, red tubular flowers, are insanely attractive to hummingbirds, the overwintering hummingbirds, as well as things like bumblebees, and I've also seen humming honeybees on this thing. So if you've got the space, because you know, again, it's big, then you can expect an evergreen shrub to be about eight feet by eight feet. But I'm sounding like a broken record to keep repeating these dimensions.

But I want people to know what they're getting themselves into, right? You do have to provide space because if it's too small of an area, then it's not going to be not going to work out. One thing I will say is that some of these things might be suitable for pots, at least in the short term for a few years before they burst the pot open with the root system. But you can sometimes, you know, grow something in a pot that's a little bit tender and maybe a little bit big for your garden in the short term and, you know, periodically take cuttings and then start a new pot. I guess that's another way of introducing these into a smaller garden without creating a pruning nightmare for yourself.

But there are some, there's a couple of plants at Chaperal Current and that, you know, Gravelia, the Gravelia Victoria, which single-handedly span the entire winter period. So that's pretty cool. I'd say. The other one we started, Ryan Contreras and I, our woody plant reader in the Horticulture Department, started a trial of Chamelea sysanqua. And that's an Asian species of Chamelea and the most explicitly winter-blooming species as well. And there are many, many cultivars of that. We have a trial down in Corvallis of 21 different cultivars which have a range of bloom times. So again, that's one of those species which, depending on which cultivar you pick, you may have a, you can fashion this relatively long bloom period from late fall through early spring, just using that one species, but different cultivars. And I have seen, that the trial is young, it was only planted a couple of years ago. So, I mean, the bloom, the blooms are still coming on, I guess you would say. And I have seen pollinators on the flowers of some of those as well. So that seems to be another one, but I mean, I wouldn't be able to say, oh, plant this one, because that's a sure winner. That's information that our trial will hopefully provide. All right.

Speaker 1: So that gives us some solid recommendations for winter plants. And I have to say, I do, I have seen that winter, that sort of the winter blooming Mahonia, and it is really remarkable how many bees it can attract. Yeah. No, it's not Mahonia. It's a different genus, the Asian one.

Speaker 2: No, Mahonia media.

Speaker 1: Okay. Perfect. So, yeah.

Speaker 2: I've forgotten now whether we're supposed to call our native one Bear Bear or Mahonia, I believe it's Mahonia Aquafolium. So they're all the same genus, which of course is a very big genus.

But Mahonia media, it's actually a hybrid, Mahonia X media. There are a number of cultivars, and we grow charity, but there are others like Hope and Winter Sun. And there's a fragrant one called, really fragrant one called Lionel Fortescue. And I've seen those for sale in Oregon or Washington. So I mean, they're out there. Sometimes, like I said, these are a little bit specialty. So a little bit of searching around in some of the more specialty retail or mail-order nurseries, but you'll find them for sure.

Speaker 1: Well, let's just quickly, what are some of the ways people go wrong with shrubs or trees? What are some of the common mistakes? And you've mentioned one repeatedly, not planning for the size. Yeah.

Speaker 2: You can do a lot with pruning, but honestly, as I said, with things like chapter current or ocean spray, other upright growing that sort of vase-shaped growth habit, you can prune without, you know, disfiguring the plant or, you know, altering the growth habit to the point where it's, I mean, the growth habit is one of the appeals, right? In some cases, the bark is one of the appeals as well. So those plants I find are actually fairly prunable and can be maintained in a relatively tidy way in a relatively small space. So we know what the height is. What you're attempting to manage is the width of the plant. And so you can be, you can have, you can do quite a bit with pruning on plants like that. Where it starts to become more problematic is where it's a big rounded evergreen shrub. And some of those like Xenothus don't really like to be sheared into smaller balls than they want to be.

They just want to be a big evergreen shrub. So it's those that I would say you need to really think carefully about how much space you can offer. And whereas you can do some size management on those with an annual shaping after bloom in most cases, it's always better and easier and less work just to let the thing go because you've got the space to accommodate it. The other thing is soil quality.

Okay. Ensure that the site is, you know, there's no compaction or anything of that nature. I mean, you do want reasonable drainage in the soil and reasonable fertility. So before planting, break the soil up if it happens to be compact, and ensure that the drainage is adequate. And the other thing is adequate exposure to sunlight. So most of what we've talked about are plants that will flower much better and remain more compact, as compact as they are, in full sun, at least full afternoon sun. So those are the major considerations I would guess. Yeah, it's this available space, reasonable drainage in the soil, and full afternoon sun at the very least, full sun if possible.

Speaker 1: Okay, great, Neil. Thank you so much. I hope to have you back on the show. I know you've got a number, as you've mentioned, you've had a number of trials going on. You've mentioned a number here, but I know you also have a ground cover trial that I'm very excited about.

Speaker 2: Yeah, it's looking good too. Part one of our ground cover trial was planted last fall, and we've got other new stuff to plant next year.

Speaker 1: So yeah, it's fun. Look forward to having back on the show, and I guess we'll see each other on Monday where we're going to be having a webinar where people can ask any question they want about pollinator gardens, including shrubs and trees. So great.

Speaker 2: See you then. Looking forward to it. In the meantime, have a great weekend.

Speaker 1: Thank you so much for listening. The show is produced by Quinn Synan-Neal, who's a student here at OSU in the New Media Communications Program, and the show wouldn't even be possible without the support of the Oregon Legislature, the Foundation for Food and Agricultural Research, and Western Sarah. Show notes, with links mentioned on each episode, are available on the website, which is at pollinationpodcast. oregonstate .edu.

I also love hearing from you, and there are several ways to connect with me. The first one is you can visit the website and leave an episode-specific comment. You can suggest a future guest or topic, or ask a question that could be featured in a future episode. But you can do the same things on Twitter, Instagram, or Facebook by visiting the Oregon Bee Project. Thanks so much for listening, and see you next week.

Shrubs and trees are key to any landscape designed for pollinators. This episode we tap OSU’s shrub and tree expert to list the top picks for spring, summer and winter and to learn how to care for them.

Neil Bell oversees the Master Gardener program in Marion County and Polk County and works with my volunteers to assist homeowners with their garden problems. His research interests involve evaluating evergreen shrubs for un-irrigated landscape applications in western Oregon. Since 2001, he has done evaluations of Ceanothus, Cistus and Halimium at the Oregon Garden in Silverton and at the North Willamette Research and Extension Center (NWREC) in Aurora. Currently, he is evaluating Grevillea and Arctostaphylos for hardiness, growth and flowering at NWREC. He uses these results to design low-input landscapes for the region that emphasize year-round ornamental appeal. He is also an author on two new publications for pollinators and landscape design.

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