When the wood inside a trunk is decaying, the bark separates from it. Since there is so much bark falling away from this pecan tree, there may be a large portion of this trunk that is being consumed by the decay.

Dear Neil: After reading your helpful advice for a long while, I now fear I need some personally. I had a relatively minor limb cut from my pecan tree less than one year ago. Now there seems to be a very large amount of bark falling from the trunk following recent winds. I don’t know that it’s related to the trimming, but I’m very concerned. What might be happening?

I’m going to begin with the black, water-soaked streak that’s coming down the side of the trunk. That tells us that there is active decay within the trunk. Most commonly that starts with a small branch that hasn’t been pruned properly several years in the past. If a stub is left in place, perhaps even after a branch has broken off, the wound can’t heal properly across the freshly exposed surface and decay sets in. It moves up and down almost in a straight line as you are seeing. You can usually trace that line to find the source of your trouble.

And then to your question about the bark. When the wood inside the trunk is decaying, the bark separates from it. Since there is so much bark falling away, there may be a large portion of this trunk that is being consumed by the decay – enough so that I’m concerned that you may not be able to save the tree. You need to have a certified arborist look at this tree immediately. It could be weak enough that a strong wind could topple it once it leafs out.

Dear Neil: Please tell me that I wasn’t the butt of a joke when, about 30 years ago, an old friend told me that to be successful when transplanting a dogwood tree, you had to position the branches aiming in the same direction they were before it was dug. I did transplant one using that theory and it’s flourishing. Was there any truth to that recommendation?

Whatever works for you. I don’t believe you’ll find any forestry or horticulture school teaching that, but it sounds like something worked right, so let’s just give it credit this time. Fact is, getting the root ball at the same depth at which it was before the dig is a lot more important. So is staking and guying any tree that is large enough to be blown out of plumb by the prevailing winds of the summertime.

Dear Neil: One of my live oak trees was ravaged by the little wooden “marbles” on its twigs last summer. They’re still there, and I’m wondering if they are harmful to the tree. Is there anything I can do now to prevent them from producing more of these things next summer?

Those are called “woody oak galls,” and they’re extremely common. They’re not especially harmful to the tree, but they are unsightly, especially when you get them all over the branches. They’re the work of female wasp-like insects that sting the small twigs and lay eggs in the young tissues. The galls are the plants’ reactions to the stings. All that, and now the letdown: there is no prevention and there is no cure. As a wise entomologist once told me, “You might as well learn to brag about them.”

Dear Neil: If I want to divide my mums, when should I do it?

The old rule of thumb is that if it blooms in the spring, you divide it in the fall, and if it blooms in the fall, you divide it in the spring. However, mums get a fast start on growth in the spring, so you don’t want to wait too long. You can see this year’s stems at the bases of last year’s flower stalks. Sometime in mid- or late February, on a warm, sunny day, you can dig up a clump and cut or break it into smaller clumps two-thirds the size of a tennis ball. Replant those into freshly prepared garden soil in a well-draining, sunny location.

Dear Neil: Have you ever tried to grow Irish potatoes in bags?

Specifically, no. There are so many odd ways that get thrown out for growing potatoes. I’m unsure why anyone thinks they’re better than planting directly into raised gardens filled with highly organic soil.

Potatoes are some of the most delicious fresh vegetables you can grow in your home garden, and planting time is upon us. Start with certified seed potatoes from a nursery or feed store. Those are tubers that have been grown specifically for propagation. Cut them so that you’ll have three or four eyes (buds) per piece. Lay the pieces out to dry on newspaper for a couple of days prior to planting. Dust them with sulfur or a labeled fungicide, then plant them in trenches 6 or 7 inches deep. As the plants start to grow use a hoe to pull soil over the tubers carefully until you’re back to the original grade of the garden. Keep them moist at all times and fertilize them every couple of weeks with a complete-and-balanced fertilizer. “New” potatoes will be ready when the plants have come into bloom. Baking size tubers will be ready a couple of weeks later, about the time that the tops start to fall down. That’s all a lot simpler than trying to grow them in bags.

Dear Neil: How are snake plants propagated? I understand some types can be rooted from leaf cuttings, others cannot. Why the difference?

If you think about the different types of sansevierias, you’ll recall that some types have cross-banded markings across their leaves. Other types have bordering bands of yellow or white stripes around the outer margins of their leaves. Those that have the stripes around their edges are referred to as being “chimeras.” When they develop roots and start to send up new leaves, the leaves will be partially green and partially white or yellow. Where the new sprout forms will determine where the split in color will be, but it will definitely not be all around the outer border of the leaves. Those varieties can only be propagated by division of existing plants. By comparison, snake plants with cross-banded markings propagate easily from leaves that are inserted into very porous rooting media containing one part of sphagnum peat moss and two parts of horticultural perlite.