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Amy Grotta's Tree Topics
Serving small woodland owners and managers in the Willamette Valley and northwest Oregon
Updated: 4 days 10 hours ago
By Amy Grotta, OSU Forestry & Natural Resources Extension, Columbia, Washington & Yamhill Counties, and Paul Wilson & Linda Farris, Columbia County Master Woodland ManagersFlowering currant seedlings awaiting transplant. Photo: Paul Wilson
When Paul Wilson and Linda Farris bought their small property about 10 years ago, it was a reforestation failure. But they have succeeded in beating back immense Scotch broom and other invasives and have planted a diverse mix of trees. Not stopping there, they continue adding diversity by releasing native shrubs that don’t get in the way of their planted trees, and by planting more native shrubs and herbaceous plants to occupy gaps where the invasives used to be.
Paul and Linda propagate most of their own plants from seed and cuttings, having learned over time what methods work for different species. They shared their experience on a recent Twilight Tour, and afterwards agreed to write up and share their propagation tips (in the rest of this article). Thank you Paul and Linda. If you want to try your hand at this, fall is a good time to start.
How to take cuttings (adapted from Washington Native Plant Society guidelines):
We use a very low-tech approach to propagate dormant deciduous native shrubs which come readily from cuttings. By taking cuttings after the leaves have fallen, the cuttings focus on developing roots and require little care.
Use sharp pruning shears. Clean shears with rubbing alcohol or a 10% bleach solution (one part bleach to nine parts water).
Select young straight shoots about the diameter of a pencil (except trailing snowberry, which can be thinner). Collect long branches– you will be dividing them into individual cuttings later. Cut just above a leaf node. As you collect, put the cuttings in a plastic bag or the ends in a bucket of water, and keep them cool, moist, and out of direct sunlight.
To prepare individual cuttings from the long branches, clean your shears again. Cut the branches into pieces long enough to have at least three or four leaf nodes (for most species, cuttings will be about six inches long). The end of the cutting closest to the roots (the “bottom”) should be cut at a 45° angle just below a node. To not confuse the bottom with the top of the cutting (essential), cut the top at a right angle (straight across) slightly above a node.
While not essential, for some species success is improved by dipping the bottom (angled) end of the cutting in rooting hormone (Rootone, Hormex and similar), tapping off the excess.
Fill a pot (we use 1 gal. pots or treepots depending on the length of the cutting) with an unfertilized fast-draining soil mix (and in many cases perlite, sharp sand or vermiculite alone will work but cuttings need soil after rooting). Poke holes in the soil with a stick a bit larger than the cutting diameter, insert cuttings with at least 2 nodes in soil and 1 or 2 nodes above soil level, tamp soil and water in. We put 5 cuttings of most species in a gallon pot.
Leave out all winter, protecting from slugs and deer in the spring. Wait until leaf growth unfurls and gently check for substantial root development. If you have leaves or roots but not the other reinsert the cutting and wait. Cuttings can be transplanted to a soil mix in a larger container, or transplanted into native soil. During a dry spring keep the rooting medium moist. During the following summer, supplemental water will improve survival and development.Paul and Linda’s plant nursery. Woody plants under the wire frame and herbaceous perennials in the foreground. Photo: Paul Wilson
Propagation tips for individual species
Among these shrubs, red-osier dogwood, Nootka rose, cascara, snowberry, hazel, oceanspray and tall Oregon grape (in order from generally wetter to drier habitat) are ‘restoration superstars’ – they tolerate moisture fluctuations and disturbance and generally provide a higher success rate after planting. These brief propagation guidelines are adapted from Robson, Richter and Filbert, Encyclopedia of Northwest Native Plants for Gardens and Landscapes (2008).
Red-osier dogwood (Cornus sericea)
Easiest from hardwood cuttings taken late fall to late winter, no hormone required. Can also be grown from ripe fruit collected in the fall, fleshy part need not be removed unless seeds are being stored. Plant outside to stratify over winter.
Nootka rose (Rosa nutkana)
Easiest from seed removed from hips just as they ripen, planted out for winter stratification to germinate the following spring. Lower success from hardwood cuttings mid to late fall, treated with hormones and set to root over winter.
Oceanspray (Holodiscus discolor)
Easiest: hardwood cuttings in late fall or early winter, dip in rooting hormone and root in pumice or other medium. Seeds have a low germination rate: plant thickly in fall; need cold and moisture to germinate the following spring.
Beaked hazel (Corylus cornuta)
Easiest from seed; harvest slightly green before the squirrels get them; plant in fall; need cold and moisture to germinate the following spring.
Indian plum/Osoberry (Oemleria cerasiformis)
Easy from seed: Collect fruit in early summer, dry the fruits, plant in fall; need cold and moisture to break dormancy and germinate the following spring. Or, take hardwood cuttings in late winter, treat with hormone.
Serviceberry (Amelanchier alnifolia)
Collect and clean seed, plant seed in fall; need cold and moisture to germinate the following spring.
Common snowberry (Symphoricarpos albus)/Trailing snowberry (Symphoricarpos mollis)
Hardwood cuttings late fall/early winter; treat with hormone and put in soil to root. Seed requires 2 winters to germinate.
Dwarf Oregon-grape (Berberis nervosa)/Tall Oregon-grape (Berberis aquifolium)
Collect ripe berries in summer; remove some of the pulp and plant seed soon after harvest; need cold and moisture to germinate the following spring. Hard to grow from cuttings.
Blue Elderberry (Sambucus nigra)
Hardwood cuttings mid-fall to early winter, treat with hormone and root in pumice or other medium. Or, collect seed in late summer or fall, remove some of the pulp and plant seed soon after harvest; need cold and moisture to germinate the following spring
Bitter Cherry (Prunus emarginata)
Collect seed in late summer or fall, remove some of the pulp and plant seed in fall; need cold and moisture to germinate the following spring. Difficult to grow from cuttings.
Cascara (Rhamnus purshiana)
Collect ripe fruit in the fall; remove some of the pulp and plant seed in fall; need cold and moisture to germinate the following spring. Expect 2-3 seeds in each fruit.
Red-flowering currant (Ribes sanguineum)
Collect berries and remove seeds; plant seeds in flats of potting soil in fall; need cold and moisture to germinate the following spring.
Categories: OSU Extension Blogs