Protecting the Grapevine

By Jeff Rugg-
Q: We bought a grapevine on a whim at Home Depot. We planted it along a fence. It grew OK for a couple years but didn’t seem to produce any fruit.

This year, we noticed there are lots of grapes, but the birds are eating them all before we can get to them. What is the best way to beat the birds to the grapes?
A: Birds like any fruit that we like, and they seem to eat them before they get ripe enough for us. For a single vine like yours that has a limited number of grape clusters, you can try bagging the clusters. There are mesh netting bags called organza bags that have drawstring tops. They easily slip around the cluster and cinch tight.

They prevent birds and insects from damaging or eating the fruit. Organza bags also protect apples, peaches, pears and other fruits from insects. They come in a wide variety of colors and sizes.

The second thing you can do is net the whole vine. The most common and least expensive netting is lightweight polypropylene net, with a mesh size of 1/2 inch by 1/2 inch. This netting is difficult to install, as it tends to stick to itself and the vines. Woven-cloth bird netting is also effective and easier to work with but more expensive.

Q: Our iris plants seem to be overcrowded. When and how do we divide them?
A: Bearded iris plants grow via rhizomes. A rhizome is an underground stem. Iris rhizomes grow near the soil surface, and they branch out in different directions. They bloom best on the ends, and over time, the center of the clump loses leaves and flowers. They can be divided every five years to increase flowering.

Bearded iris can be divided during July through September, but early August is when it is usually done. The rhizomes have roots growing down into the soil, but they are easy to dig up. Use a sharp knife to cut the rhizome into sections that include two fans of leaves. Any leftover, single fan sections will still be planted but may take an extra year to flower. Apply a powdered fungicide to the cut-off ends of the rhizomes.

Check for iris borers while dividing the rhizomes. These are moth caterpillars. They hollow out the rhizome and kill it.

Prepare the planting area by adding compost, mixing it into the soil. Plant the iris at the same depth it was growing at before. You can cut the leaves back by half to two-thirds, if they start wilting.

Q: Help! My peony plants have developed purple spots all over the leaves. Some of the leaves have turned brown and are dying. What can be done to save them?
A: Your peonies have the measles — but not the kind that causes measles in unvaccinated people. The spots are the symptoms of a fungal disease.

There is nothing that can be done to treat the disease in the summer. The leaves were infected before the flowers bloomed in the spring.
This fall, remove all the dead leaves and dispose of them. Do not compost them. Start fungicide treatments as the leaves begin to come up out of the ground next spring (when crocuses are blooming). Treat the whole area around the plants as they come up. Keep treating the plants and soil weekly until they bloom.

Older heirloom varieties are more susceptible than newer varieties. The older varieties vary in susceptibility. Even though the disease is unsightly, it may not kill the plants, but over time, they can become weaker and produce fewer flowers.

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