question regarding sweet chestnut (Castanea sativa)

Hello Permies,

I'm addressing this question to those of you who have experience with growing sweet chestnut trees.

Situation: I planted about 20 chestnut trees (Castanea sativa) in Oct. 2013. They came in pots, and were already about 1.5...1.8 metres (5-6 ft) tall when transplanted. All of them caught on, but growth was modest (25 cm / 10 in max) the first year, probably set back by a hailstorm that struck in early summer when new growth was very tender; by autumn 2014 I could see a significant amount of die-back.

I have to note here that my site is borderline in terms of suitability for sweet chestnut: temperate climate with cold winters (last winter we had 2 weeks of particularly cold weather - minus 25 Celsius), clay soil; but good southernly exposure and good surface drainage.

There is no tradition of growing chestnut trees locally; local people see chestnut trees as a kind of exotic species. Hence, finding local suppliers of planting material is not easy, so I was happy to find one nursery that sold chestnut trees in pots.

The trees were planted at the same time with another 300+ trees & shrubs on a single day, so we had to enlist the help of the nursery in getting them planted. Even though I specifically asked the nursery people to look out for pot-bound roots and to free them before planting the tree, I suspect that, when I wasn't supervising closely, they may have planted some of the trees pretty much as they were lifted from their pots.

Issue: This Spring I have noted that (a) on some trees die-back was quite serious (in some cases as much as 1/2 of the crown); (b) a couple of trees had very slow leaf burst. However, on some trees there are new shoots from the base, which look very healthy and have achieved more growth in a couple of weeks than the crown did in a whole season last year.

Questions: seeing that my trees are not thriving, would it be worthwhile cutting them down to the ground and allowing them to regenerate from the base? If I do that, what would be the prognosis? When would be the best time for doing that? Literature recommends pruning when the tree is dormant, but does the same apply if I cut it to the ground when aiming to achieve maximum re-growth?

I have even considered digging them up one by one to check the roots and free / prune them if necessary. (The trees' current size is still manageable.)

I'd be grateful for your advice !

Levente - I manage an area of woodland with a long established chestnut coppice. I've not planted chestnuts myself so can't speak for their early growth as new plants.

What I have observed is that some plants can be slow to put on growth when the stems are young, but kind of race away when they get a bit older. Regarding possible root bound plant; I would leave them and see how they do. Chestnut is easy to propagate by layering stems, so you should be able to fill in any gaps that appear with ease.

I suspect that once your roots are well established they will thrive - ours have about 3 inches of soil on top of 200m of clay. They blow over sometimes in the wind but still seem to hang on in there.

Hello Michael,

Thanks for the advice. This sounds very encouraging.

I'll look into layering of young stems; if any survive from among those growing now, I may try it next year.

L_

You might want to dig up a random tree or two and physically check the condition of the roots. If indeed they were planted with coiled roots from being pot-bound, it's not a problem that's going to solve itself. What geographic region are we talking about here? What is the soil like? One thing I can tell you for sure is that chestnuts don't like soil that is the least bit alkaline. I think that should be the first thing to check. You want to acidify the soil around your chestnuts and supplement them with soluble metals like zinc and iron. The fertilizer IRONITE is a good choice here. Do you know how to identify metal deficiency in chestnut? Look for yellowing leaves that have bright green veins. I've solved that deficiency by making a soluble iron spray with 0.5% Ferrous Ammonium Sulfate which I actually sprayed on the trees. Add a drop of detergent to make it stick to the leaves better. Seen a positive response to that within 2-3 days.