Crop rotation key to maintaining healthy soil

Published on Wednesday, 1 November 2017 19:16 - Written by Neil Sperry, Gardener’s Mailbag

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Dear Neil: I have planted several young trees within the past several years. I have noticed that the tops of a few of them have died, but sprouts are coming up near the bases of the trees. Should I prune out the dead wood and let the sprouts grow?

 

Yes. With each tree, select the one trunk that is the straightest – that has the narrowest angle from the original trunk. It doesn’t necessarily have to be the tallest among them. You just want the smallest possible crook in the trunk down near the ground. That sprout will develop very rapidly because it has a fairly ample root system and only that one shoot to support. Keep it vertical with a solid stake and plastic plant ties. They will also protect it from being broken. You’ll be amazed at how quickly these trees will develop.

 

Dear Neil: How important is crop rotation in an urban vegetable garden? I don’t have a lot of area that gets full sun, yet I really enjoy having a garden for fresh vegetables.

 

The main idea of rotating crops in a planting regime is to avoid having accumulations of insects and diseases that are specific to certain types of plants. Soil-borne problems can get worse and worse with repeated plantings, so it’s wise to vary the types of crops you have in any particular spot.

If you can at least plant the cool-season vegetables in one area one year and another area the next, you will have accomplished a great deal. Do just the reverse with the warm-season crops. For example, nematodes are microscopic soil-borne worms that sting plants’ roots and suck the life out of the host plants. They tend to bother warm-season vegetables like tomatoes and okra, so moving those plants from one area to another can help in managing their populations. Consider container gardening in those instances when it’s practical. That way you have complete control over the soil those plants are growing in.

 

Dear Neil: Last year we had a massive crop of red oak acorns and a resulting massive crop of red oak seedlings. I tried to pick up as many as I could, but we still ended up having to pull scores of them out. We have another big crop this year. Is there any way around a repeat performance? It’s so bad I really wish I didn’t have the tree.

 

Oh, be careful what you wish. Most years won’t be like this, and you have one of the finest large shade trees in all of Texas. Acorns are a tiny price to pay. I have several large red oaks in our landscape, and we use a power blower to get as many of the acorns out into open ground where they can be scooped up and mulched into the compost. I also put a 2-inch layer of shredded tree leaves or finely ground pine bark mulch (whatever I have available) around my shrubs and in my beds. The acorns fall into the mulch and can easily be hoed or pulled out. It’s much easier than trying to pull them out of tight soil.

 

Dear Neil: We’ve just bought a new house, and it has a loquat in the backyard. We’re new to this climate, and we’ve never grown this tree before. How should we go about pruning it to ensure the best growth?

 

Loquats are interesting plants. If you planted one out in the middle of a meadow estate it would develop into a lovely and large shrub. It would have a single trunk, but it would have branches completely to the ground. In that respect, they’re somewhat like small-scale versions of our magnificent southern magnolias. And that comparison gives a hint of my answer: It’s pretty much a matter of personal preference. Many gardeners leave most of the lower branches in place if they have loquats in wide landscaping beds, but you can also remove lower limbs if you prefer to have ground cover or low shrubs beneath them. Just don’t remove lower branches too far up on the trunk. Once you do that you can never get them to grow back.

 

Dear Neil: I have a tree-form shrub that has been trained with three trunks. Two of them are adjoined and one is separate. One of the adjoined trunks seems to be dying. How can I extricate it, and how can I reshape the tree to grow full and beautiful again? What might be going wrong?

 

It’s really hard to answer without a photo. It may be that there is some type of poor branch union between the two trunks and that one is being starved of moisture and nutrition. You see that fairly often, for example, with ornamental pears. Trim out the dead trunk, making the cut as flush to the healthy trunk as you can so that it can heal across the open wound. You may need to prune some of the healthy portion of the top growth out to reshape the plant as it fills back in. It might be best if you took a really good printed photo (not on your phone) to a Texas master certified nursery professional at a local independent retail nursery and ask that the photo be marked for exactly how the plant should be trimmed.

 

Have a question you’d like Neil to consider? Mail it to him in care of this newspaper or e-mail him at mailbag@sperrygardens.com. Neil regrets that he cannot reply to questions individually.