Tuesday, April 24, 2018
Home and Garden

Ask Dr. Hort: Weedy vines must go

You'll need to yank the weeds to save the azaleas

Q: I have quite a few mature azaleas in my landscape. They average 4 to 6 feet tall and wide and have grown together to form a continuous bush.

Unfortunately, they are becoming covered with three different vines that are weeds. I cannot poison the weeds without injuring the azaleas because they originate under the plants. My only solution is to pull the weeds by hand. I cannot easily get underneath the plants due to their size. I believe to eradicate the vines/weeds, I need to trim the azaleas much smaller so that I can groom around them.

My question is: Given their size and age, how small can I trim the azaleas back and not kill them?

Jim Nelson

A: A rule of thumb when pruning shrubs is to remove no more than one-third of the foliage with any pruning event. This is the time of year (June, July, August) for pruning plants back because of the rainy season and quick rejuvenation. It is also a good idea to fertilize with a quality product with 30 to 50 percent slow-release nitrogen. Use 10-0-10, 8-2-12 or 13-3-13 after pruning to push the new growth. Review the fact sheet "Pruning Trees and Shrubs" as a guide before your pruning experience at edis.ifas.ufl.edu/pdffiles/MG/MG08700.pdf.

However, you'll still have the weedy vine problem. There are three very invasive weedy vines in shrubbery:

Balsam apple, Momordica balsamina, has small, watermelonlike leaves, yellow flowers, an orange fruit pod that pops open to reveal bright red seeds, a corky, tan stem and green tendrils for climbing. When pulled, balsam apple is really stinky!

Virginia creeper, Parthenocissus quinquefolia, has palmately compound leaves (five leaflets arranged like fingers on your hand) with red tendrils for climbing with sticky discs at the end, clusters of greenish-yellow flowers, small purple fruits when ripe and a reddish-brown woody stem.

Creeping cucumber, Melothria pendula, has small yellow flowers followed by small cucumberlike fruits that turn black when ripe. The leaves are waxy, green and trilobed, with a corky, tan stem (like balsam apple) and curly green tendrils. When pulled, it smells like cucumber.

You need to follow the vine down through the bush and look under your azaleas for these stem types where they enter the ground and yank 'em out or you'll never get ahead of the "Jack and the Bean Stalk" problem.

It looks to be the invasive air potato

Q: Included is a photo of a puzzling seedless fruit found in a yard in New Port Richey. We have visited several garden centers and nurseries to ask them to identify these, but with no success.

Sizes vary from 1 inch to 3.5 inches, and some are ready to sprout, as evidenced by the one on the left. One person said that her grandmother called it Priestess Nut from a vine, but a search on the Internet found nothing by that name.

We see that some vines above the drop area have been cut.

Any information to satisfy our curiosity would be appreciated.

Ove and Mary-Ann Ojaste

A: The picture of your puzzling fruit looks to be air potato, Dioscorea bulbifera, a terribly invasive twining vine with large heart-shaped leaves (at left) that will totally engulf the canopies of trees, eventually killing them.

The following link describes it in detail: plants.ifas.ufl.edu/node/133. It is our version of kudzu.

A mystery specimen of origins unknown

Q: The attached photo was taken on March 21 in a flower bed in Safety Harbor. It is so unusual I thought it might make an interesting photo in your garden section. At least a good addition to your collection.

If you can identify it for me, I would appreciate it.

Walt Plaag

A: You have been invaded by space creatures! No, actually it's a kids toy called a "puffer ball" that has weathered a bit in the sun, as identified by my colleague Andy Wilson, senior horticulturist at the Pinellas Extension Service.

As he put it, "I don't think it is a puffball or anything of biotic origin."

I must admit, your creature defied the laws of plant pathology, though a simple touch may have solved the mystery. Even my wife, Leslie, said it looked like a Tribble from Star Trek.

Take a look at the following link for a positive identification: amazon.com/Puffer-Balls-Inch-Dozen-Bulk/dp/B0087QMEV2 and put some age on it.