Transplanting mature high bush blueberries

Question

This past spring I was given 2 mature high bush blueberry plants. They were around 6 feet high and 5 feet wide. They did produce a decent amount of berries too.

A gardening friend told me that, although they did produce berries and look relatively healthy, that they probably wouldn't survive through the winter, saying that mature blueberries bushes usually don't transplant well.

Is there any truth in that statement? If so, what can I do to help them through the winter?

I live in south-west New Hampshire, zone 5b.

Answer 1

The reason for concern is that winter damage is usually via drying, and in newly transplanted shrubs, the roots (because of the transplanting) are structurally damaged and cannot hydrate the plant as efficiently as an established root system.

Your plants, being in the ground since April, and having put out a good amount of new growth, show that the plant has put out considerable root growth also (a good percentage in the form of root hairs). In other words, you really shouldn't have a problem. Now if you have any dry spells, going into winter, so long as the ground isn't frozen, I'd encourage you to irrigate. In any case, mulching (~3" deep with some organic matter) will be very beneficial and I recommend that you do that.

These plants are very cold hardy, and cold isn't the issue unless they are too dry, then they'll get wind/winter burn. Your plants seem great, and I'd expect very little to no winter damage on them. In the case of some winter burn occurring, wait until the growth flush (or bud break) in spring and trim out any dead.

Also, if you fertilize, don't fertilize this fall, because that can promote more growth, that may not get a chance to fully harden before cold weather sets in, and that will render your plants more susceptible to winter burn. Fertilizing in the spring is a great idea, though, and I highly recommend doing that. Natural fertilizers are healthier for your soil and plant than chemicals.

Answer 2

I think your gardening friend has a point, because the longer the plant has had time to establish itself the better.

I guess the problem with highbush blueberries is that they'll stick out of the snow and are exposed to much lower temperatures than smaller plants which would be covered by snow.

Something that works even to keep palm trees alive during long snowy winters is large rocks which retain heat (provided they're placed not in the shadow, but are actually heated with sunlight, of course). Depending on where your bushes are located, placing large rocks next to them might help to alleviate the detrimental effect of the cold. Generally, the heat retention of large rocks is said to allow one to grow plants from 1-2 zone higher. Whether this will work as promised in your situation depends very much on the level of sunlight, the amount of snow, wind and the weather in general, of course. In New Hampshire you seem to have a decent amount of winter sunshine, which seems to be a good start.