Texas gardeners are grateful for plants that have a will to survive. However, several common landscaping plants make enemies because of their propensity for sending up new shoots, sometimes many feet from the mother plants — and usually not where they’re wanted.
Some of these are plants we shouldn’t be growing in the first place. Others are plants we can learn to contain. Here are some of the most common, along with suggested coping skills as you deal with them.
No plant is more invasive. It comes up on the other sides of busy streets. It overtakes tall screening shrubs. Some cities go so far as to ban it. Left unchecked, it might take over the world. It would be nice if the clumping types of bamboo (non-invasive) could be used in our landscapes. Unfortunately, almost all are sub-tropical, incapable of surviving our winters.
If you have golden bamboo creeping in from a neighbor’s yard, try to persuade them to remove it entirely, even if it involves hiring a landscape contractor with a small front-end loader. Glyphosate herbicides applied at the maximum listed rate will do a reasonable job if applied to vigorous new growth in late May or June.
If that’s not possible, your only hope will be to dig a trench 30 inches deep and either fill it with concrete or with some type of other long-lasting barrier.
Better yet, never plant bamboo in the first place!
You’ll see the native wild form growing along roadsides, train tracks and embankments. It’s durable, almost pest-free and long-lasting. If you want to eliminate it from your own yard, cut the mother plant off at the ground. Drill into the stump with a 1/4-inch bit, making several holes per stump, and fill them with a broadleafed weedkiller (containing 2,4-D) at full strength.
It will soak into the stump, so that it can be carried out to the sprouts. You may have a bit of touch-up work the following spring.
There are actually several fine types of nandinas that many of us consider to be among our best landscaping shrubs. Many do spread, but green metal edging driven flush with the ground will usually contain them. Or you can dig and divide the offsets and use them to fill empty spaces in your landscaping beds.
These shrubs are native to Southeast Texas, and no one used them commonly until the early 1960s. That’s when landscape architects started calling for them to be “limbed up” and used as small accent trees. Occasionally, they will send up sprouts 15 or 20 inches out from the trunks. I have mondograss growing around my yaupon trees, and I use a sharpshooter spade inserted 2 or 3 inches into the ground at a 30-degree angle to sever and remove them. It takes 10 or 15 minutes per year.
A certain percentage of our wonderful live oaks have the genetic predisposition to send up sprouts (“suckers”) all through their root zones. It’s unfortunate, because there is no spray you can use to eliminate them. You can mow or trim them off, but they’ll end up looking like a groundcover of live oaks. You can dig them by hand with the same sharpshooter trick, but you may not have time for much else.
Only 10 or 15 percent of our live oaks do this, but those that do are quite annoying. I wish I had a better solution.
Some people erroneously refer to this uncommon tree as “silver maple,” but it’s decidedly different in appearance. It has 2-inch leaves that are very dark green on top and powder white on the reverse. It sprouts up everywhere, and hand digging is the only remedy.
This is Ruellia, and it spreads freely through a bed of perennial flowers. If you can plant it where it will grow by itself (for example, within a concrete-edged bed), it’s a handsome heirloom flower. If you can’t, stick with the far more mannerly dwarf types like Katie’s dwarf.
Most of the mints, in fact, spread very abundantly. If you use 4-inch metal edging driven flush with the soil, it won’t usually grow beneath and beyond it. If it does, install a deeper barrier. It’s a great shade ground cover and herb, so make whatever allowances you must to be able to contain it.
People tell me that it has invaded their lawns, but in all the cases I’ve seen when I’ve stopped by friends’ houses, the edging was driven only halfway into the soil. When the ground is wet, pound the metal in the rest of the way and you should be able to stop the spread of the ground cover.
If it comes through the seams where the metal edging butts up against the next piece, consider overlapping the edging by 4 or 5 inches, or cut inserts that can be used to cover the seams.