Can you prune a tree after the leaf buds swell? How can you tell if the soil is warm enough to plant? Master gardener Paul James has the answers:
Q: I need to prune some trees, but the leaf buds are beginning to swell. Is it too late?
A: No, it's not too late, unless the trees you plan on pruning are beeches, birches, elms or maples. Those trees have a tendency to bleed profusely (release a lot of sap) when pruned in the spring, and that can lead to insect and disease problems. All other trees--whether deciduous or evergreen--can be pruned in early spring without causing any undue harm.
Spring is a good time to prune deciduous trees, because when they're leafless, you can see what branches need to be removed. You might want to hold off on spring-flowering trees such as dogwoods, redbuds, callery pears and star magnolias so you can enjoy more blooms.
Q: How important is soil temperature, and can it be used as a planting guide?
A: Soil temperature is the surest way to know when the time is right to plant--especially when planting from seed. Some seeds will germinate only in cool soils, and others only in warm soils.
Some weather forecasters report soil temperatures, but you can measure it yourself with a special soil thermometer. Just insert the thermometer into the soil to a depth of three to four inches and wait for the temperature to register, which shouldn't take more than a few minutes.
Keep in mind, though, that soil temperatures can vary several degrees from one day to the next depending on the weather. If you're looking for a certain temperature--say, 55 degrees, which is ideal for most cool-season crops--wait until you've recorded that temperature for three consecutive days before you plant. There are several books-- as well as agricultural extension publications-- that show the ideal soil temperature for various seeds, especially vegetables.
Q: Should I buy my roses bare-root or in containers?
A: It really doesn't matter, although bare-root roses arrive in the nurseries earlier and can be safely planted in late winter to early spring. They are also cheaper and very often you'll find more varieties to choose from. Bare-root roses are also easier to plant, less likely to suffer from transplant shock and are prepruned. When planting, just make sure you don't bury the graft union (the swollen portion of the stem where the top part of the plant was grafted to the rootstock) unless you live in extremely cold areas.
Q: Is it ok to apply mulch now?
A: That depends on what you are mulching. In the vegetable garden, most cool-season crops that grow in spring will benefit from a light layer of mulch, because it helps keep the soil cool. But in flower gardens and ornamental beds, you might want to wait a few weeks so that the sun has a chance to warm the soil, because those plants prefer warmer soil conditions.
Q: Help! I followed your advice and covered a clay-filled bed with straw to improve the soil, and now I have weeds popping up all over the place. What do I do now?
A: Assuming you did use straw rather than hay, what's popping up all over the place is probably wheat, and that's not necessarily a bad thing. Wheat straw often contains wheat seeds, which readily germinate and serve as a green manure. You can easily pull up the emerging clumps of wheat and leave them on top of the soil to decompose or you can let them continue to grow and their roots will penetrate into the soil to loosen it. If what you bought was hay, however, that's another story. Hay, particularly prairie hay, can contain all sorts of weed seeds such as thistle, and they should be removed as soon as they appear.
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