I purchased some good sized (3-5 gallon) blueberry plants yesterday. I was reading the OSU extension pub EC 1304, which emphasizes heavy pruning upon planting (and removing all fruit buds to prevent berries the first year). I really want to ignore this advice because the plants have nice flowers on them now and I'm eager to get fruit this year. I thought I could ignore the recommendations since the plants are so big already -- at least 2 ft tall and around. Unwise?
I have seen the blueberry plants you refer to for sale.
While it is best to follow the advice in my publication, many, like you, are very tempted to taste some fruit the first year. The reason we recommend pruning the plant back in the dormant period or during bloom (if you are buying in spring) when you first plant is that producing fruit on a young plant is such a drain on the plant's resources. We've shown dramatic reductions in plant and root growth when plants are allowed to fruit when they are young.
Take a look at the photo. These plants were dug up in the winter after the second fruiting year:
- the plant on the right had all of the flower buds pruned off at planting and was allowed to produce very little fruit the following year;
- the one on the left was allowed to produce all of the fruit present in the planting year and a full crop in the second year.
I think you can see the large differences in growth (root and above ground plant). We saw this in all the varieties we studied.
If you prune to remove or greatly limit fruit in the planting year, the plant will put all its energy into new shoot and root growth. This will benefit the plant in the long term.
If the soil is well prepared, including soil pH in the 4.5 to 5.5 range (see Growing blueberries in your home garden, EC 1304), then the plants will live for over 35 years. You want to get them off to a good start.
Even though the plants you bought look large enough to produce fruit, they will still greatly benefit from the pruning recommended in the publication.