Neil Sperry: Answers to common questions before North Texas gardening season ramps up
As the new gardening season ramps up and starts running it seems like we have more questions than ever before. Let’s address a few of the common ones.
What should I do with my waxleaf ligustrums? They look terrible after the Christmas freeze.
If they look like someone walked on their leaves with hot cleats, that’s totally freeze damage. Scratch the bark on the twigs in several places. If it’s dry and brittle the plant has died back and those branches can be trimmed away. If you’re not sure, however, you can leave them in place for another five or six weeks to see if the plants offer to sprout out. That will give better definition to the extent to which you’ll need to trim them.
Has the most recent cold changed the timing for planting our spring vegetables?
Not at all. It still takes a certain number of days for any vegetable crop to reach desired maturity. Plant too late and your crops will hit the wall of late spring and summer heat. If cold or rain delays planting at the prescribed time, find another crop that you like almost as much and concentrate your space and effort on it. Late plantings seldom work out well.
When should I prune my blackberry plants? They’ve grown into a tangle.
That’s going to be a late spring task. Any given blackberry cane only bears fruit once. When you have harvested fruit from that cane you must cut it completely to the ground. It will never bear fruit again. New canes will be developing around it. Pinch or prune their growing tips out to keep them from getting too lanky. In the process you will encourage side branching for more fruit the following spring. This is something you must do every year.
I see holes all over the trunk of my live oak tree. What causes that, and what can I do to stop it?
Almost always that’s the work of a woodpecker. If so, the holes will be in straight rows as if a machine gun had been fired across the trunk. Woodpeckers are incredibly busy birds, but the good news is that the holes represent no cause for concern. The holes are relatively superficial and major damage is almost never done. You don’t want to harm the birds (plus it’s illegal). Just learn to enjoy watching their activities.
I had nutgrass and bermuda in my vegetable garden last summer. What can I put out now to kill prevent them this year?
These are perennial weeds, so pre-emergent weedkillers will not work on them. There is nothing you can do now other than rototilling and raking to remove the weeds by their roots (not a very effective means of control). Both of those weeds are best dealt with during the summer while they are growing actively. Once you have harvested the last of your spring crops and your garden is empty, you can use a glyphosate herbicide (no other active ingredient included) to kill the bermudagrass.
As for the nutsedge, use either Image (the product specifically for nutsedge control) or Sedgehammer in the summer. Both take a period of time to kill out the nutsedge.
Is it good to scalp your lawn? If so, when should I do it?
Scalping is optional. However, it does eliminate many of our spring weed problems, notably things like henbit, thistles and other tall, coarse types. Drop your mower blade down one notch. You’ll be removing all the blades that were browned by the freezes. In doing so you’ll expose the soil to the sun’s warming rays. That will encourage your turf to green up more quickly and it will get the dead grass out of the way.
Early March is soon enough. Scalp turf too early and you run the risk of a late frost setting the lawn back. And don’t send your clippings to fill up the landfill. Find a composting recycle center or compost them yourself. They can supply valuable organic matter and much-needed nutrition.
How should I prune my rose bushes and when?
Trim them by the middle of February, preferably early in the month. Aim to trim bush roses back by half as you make each cut directly above a bud that faces out from the center of the plant. That will encourage more open branching.
As you’re pruning your bushes, check closely for signs of rose rosette virus. It’s a fatal disease for which we have no preventive measure, nor do we have any cure. It is spread by a wind-borne microscopic mite. Unfortunately, we can’t do anything about that pest either.
There are several telltale symptoms of RRV. During the growing season buds will develop to a certain point and then fail to open properly. Some of the canes will have 10 or 12 times the normal number of thorns. You are likely to see an unusually strong “bull” cane coming out of the middle of an infected plant. The plants go downhill for a year or two before they ultimately decline and die.
Dig and remove any plant that has RRV as quickly as possible to prevent the disease from being spread to other roses in the neighborhood. Send it to the landfill. Do not take it to a nursery for confirmation of the disease. They don’t want it near their plants. All rose varieties are susceptible.
You may want to switch major plantings to other types of flowers until some kind of resolution is found for rosette. This disease has been epidemic across North Texas for more than 10 years. It’s been known worldwide for decades, yet we still are miles from any solution.