This Bradford pear was split by the wind last season. (Contributed Photo)

Dear Neil: What is the best way to feed and prune a number of Nellie R. Stevens hollies we planted five years ago in order to encourage vertical growth?

Before I try to answer that, let me remind you that it’s difficult to change genetics. If we never pruned a Nellie R. Stevens holly it would grow to be 20 feet tall and 12 or 14 feet wide. It would be, more or less, in a Christmas-tree shape. It would be difficult to transform that into a columnar type of upright-growing shrub.

Now that I’ve established that boundary, you can encourage upright growth by trimming away any new branches that are developing into a spreading habit. Prune just above buds or twigs that face upright in the canopy of each plant. Hopefully your plants haven’t grown so large that that kind of pruning would disfigure and denude them. It’s always best to train plants from the day you set them out into the landscape.

If you ever have a similar decision to make in future years, a couple of other plants might be more suitable. Oakland holly grows in the form it sounds like you want. And certainly two upright forms of yaupon holly would qualify: Scarlet’s Peak and Skyward.

Dear Neil: I’m going to be taking two Bradford pears out. Each of them has split just as you have warned us they would do. A neighbor did the same thing a couple of years ago and they have had an onslaught of sprouts coming up all over their yard. What can I do to avoid such an issue?

Bradford and other ornamental pears are grafted onto rootstocks of Callery pears, and when we have to have a damaged Bradford removed the rootstock quickly sends up all those sprouts in an effort to keep the species alive and going. The best way to avoid as much of that as possible is to have an arborist grind the stump out. Have them take the crown of the tree out as well as all major roots. Hopefully they’ll be easy to eliminate. Any sprouts that still do manage to emerge can be dealt with by spot-applying a broadleafed weedkiller containing 2, 4-D to each sprout. If you can’t find someone with a stump grinder, drill large holes into the stump and pour the 2, 4-D herbicide to fill the holes. It will be carried out through the roots. Do this drilling in mid-February.

Dear Neil: I had a foxtail fern in a pot on my patio last week during the cold weather. It is unhappy pale and it’s dropping its leaves now. Do they freeze? I thought it was an asparagus, so I thought it would be able to survive.

They are indeed Asparagus meyeri. But they’re not nearly as cold-hardy as the garden asparagus that you see clear into Canada, where temperatures drop well below zero. My references say it should survive light freezes, but I get mine into my greenhouse anytime freezes are approaching. Trim off the dead tops and put it into a protected spot for the balance of the winter. Perhaps it will come back out with plumes of new leaves in the spring.

Dear Neil: Can I trim and reshape my Texas sage plants? Ever since the cold spell several years ago they have become very leggy. When should I do it?

Trim them in the next four or five weeks, before new growth commences. You can remove 30 to 40 percent of their top growth, but do so one branch at a time, so that you can maintain some semblance of normal shape to the plants.

Dear Neil: Topsoil in my landscape has shrunk away from sprinkler heads and the walk. Does it disappear? Should I be adding more?

You must have a clay soil. Clays expand and contract when they get wet or become dry, respectively. I used to play golf, and the place that was most affordable was a community course that was never irrigated. One summer, I actually lost a golf ball that rolled into one of the cracks in the dry soil. To my horror, I saw it happen. There is nothing you need to do now. You’ll notice, after rains, that the problem abates.

Dear Neil: I saw your recent instructions about planting bermuda sod, but I want St. Augustine. Are they handled in the same way?

Yes. Both need to be planted onto carefully rototilled soil that has been raked smooth using the back of a garden rake. Take care to snug the pieces of sod together, and water the new grass as soon as it’s been laid.

While you’ll see landscape contractors planting bermuda sod in mid-winter, it’s really better to wait until spring (late March through mid-May) for both bermuda and zoysia. It’s absolutely imperative that you wait until the weather is considerably warmer to plant St. Augustine.

Dear Neil: Do you recommend putting broken flowerpots or gravel in the bottoms of large pots to improve drainage when I’m repotting my houseplants?

They won’t improve the drainage at all. That assumes you have a drain hole in the bottom of the pot in the first place. That’s a must for starters. If you don’t have one, drill one. You can even drill through glazed clay pottery if you use a masonry bit and a constant supply of lubricant to keep the bit from over-heating.

You improve drainage for your houseplants by using a porous potting soil. For me, that would consist of 40 to 50 percent sphagnum peat moss, 20 percent finely ground pine bark mulch, 10 or 20 percent well-rotted compost, and the rest expanded shale. Blend all those together and you’ll have a potting soil fit for a king’s garden. From that point on your main goal will be to keep the plants’ roots from plugging up the drain holes.