Thorny Smilax vine nothing to smile about

By Audrey Post
MS. GROW-IT-ALL

Q: I have an invasive vine in my yard that is very thorny. It has long runners and breaks when I pull it up by hand. How can I get rid of this thing?

A: From your description, it sounds like smilax, a nasty customer indeed. Also known as catbrier, deer thorn and blaspheme vine (very appropriate!), it has a long tap root with small bulbs that form around it, so pulling it up really doesn’t work. Some types of smilax have heart-shaped leaves, while others have elongated narrow leaves.

If you can catch it in early spring, your best bet is to dig it out. Make sure you get the entire mass of roots. Gloves are must because once it has sprouted, those thorns are wicked. Smilax particularly likes azalea bushes, so prune them once they’ve finished blooming so you can get under the branches to dig out the smilax root.

You can spray smilax with a weed killer for brush and woody vines, but chemicals tend to run off instead of soaking in because the leaves are glossy. Plus, it’s too easy to hit nearby plants with the spray. I have used a small foam paint brush to “paint” the leaves with herbicide, which knocks it back for a couple of months but doesn’t kill it. Another one of those bulbs simply takes over. I suppose if I kept at it at regular intervals, I might eventually kill the thing.

Walter Reeves, host of the Gardening in Georgia show on Georgia Public Television, suggests the following method:

Using Roundup concentrate, make up three gallons of solution following label directions in a five-gallon plastic bucket. Lift the long vines off your shrubbery, flowers and wherever else they have deposited themselves and drape them into the bucket. Let each vine soak about 15 minutes, so it can soak up as much poison as possible. Be careful when you lift out the vines that you don’t sling poison on nearby plants. Lay the soaked vines on the ground and let them dry.

You can strain the trash out of the leftover Roundup in the bucket and reuse it. Take an old strainer, line it with a coffee filter and pour the solution into a pump sprayer.

Wait until crinum's foliage dies to prune it

By Audrey Post
MS. GROW-IT-ALL

Q: My crinum lilies are looking a little ratty. Most have finished blooming. Can I cut the browning foliage back or will it hurt the plant’s performance next year?

A: It’s the time of year when lots of summer-blooming perennials start to look a little rough. While it’s OK to cut back some spent plants, you should leave your crinum lilies alone. As long as foliage still has some green, photosynthesis is still happening and the plant is storing food for the winter and for next year. If you cut off those less-than-perfect strappy leaves, the size and bloom could be affected next year. Just like daffodils, you want to let crinums die back naturally.

If the foliage has turned completely brown and crumbles when you touch it, it’s finished. Go ahead and pull it out. You won’t even need to cut it.

If your plant isn’t quite to that stage yet and its appearance really disturbs you, set a big pot in front of it full of fall mums. Or you could divert the eye with a stunning display of fall color in another part of the yard. Area nurseries are full of fall bloomers and end-of-season summer perennials.

Q: I have a very large grapefruit tree, at least 10 feet tall, that until two years ago was kept in a pot. It has lots of thorny branches. Is this typical of grapefruit? I have a Satsuma tree that will get some thorny limbs and my neighbor told me to cut them off. The Satsuma has finally begun to bear after five years. The grapefruit has not flowered or set fruit. I live in Killearn Acres and the tree is in full sun with afternoon shade. It faces east. Should I cut off the thorny branches? How old do grapefruit trees have to be to set fruit?

A: Some citrus trees have thorns, some don’t. Many of the more modern hybrids have been bred not to have thorns, but I’ve never known of thorns to make any difference in whether a citrus tree bears. Two of my citrus trees have thorns; the rest don’t. They all bear.

Do you know what variety your grapefruit tree is? Some are slower to bear, and your tree might not be ready yet, especially since it was in a pot a long time. It could be putting its energy into getting its roots established.

I know of a grapefruit tree in Killearn that is loaded right now with ripening fruit, but it’s at least 30 feet tall and has been there for years.

I suggest you get the soil around the tree tested to see whether it’s deficient in any major or minor elements, and fertilize next February.

Footnote on Leyland cypress canker: After reading last week's column on Leyland cypress canker, Stan Rosenthal, Leon County's extension agent for forestry, noted that foliage blight can present similar symptoms to canker. "The difference has more to do with the pattern of the browning of the foliage," he said, "but both can be avoided by not over-planting any one variety."