GARDENING Here's to having healthy hostas

Nothing can be done once plants get a certain virus, an expert says.
KNIGHT RIDDER NEWSPAPERS
NEWPORT NEWS, Va. -- There's always some pest or disease lurking among Frank Hunyady's hosta collection.
He takes it in stride, however, realizing there's no such thing as a problem-free yard, especially when you grow 300 varieties of this shade-loving plant.
"Look at that," says Hunyady, who lives in Newport News, Va.
He points to Elvis Lives, a hosta that belts out a 60-inch-wide clump of blue-suede leaves when it's feeling fit as a fiddle. But this plant is no longer a star in the garden because it's infected with Hosta Virus X, which shows up as irregular yellowing on the foliage.
"Once it starts, it's all over," says Hunyady, shaking his head with disappointment.
Hunyady avoids touching the plant even with the toe of his shoe because handling a sickly leaf or using a cutting tool on it transmits the virus to a healthy plant. That's why it's important to wash your hands with soap and water and disinfect your pruning tools with a mild solution of bleach and water between gardening chores, he says.
Insidious disease
Symptoms for HVX, the virus's nickname, vary from cultivar to cultivar. Dark green or blue markings appear on light green leaf tissue; on darker green tissue, the virus causes a yellow mottling. Variegated plants such as Striptease can fool you because you think the mottling is part of its attractive variegation. But it's not, says Hunyady. He's learned all this during online chats with hosta researchers and hobbyists like himself.
Because nothing stops HVX, you need to remove and trash infected plants. Do not compost them, or you risk spreading the disease. You can put new plants in the same spot because the virus does not live in the soil.
Now, breathe a sigh of relief, says Hunyady, because most other hosta headaches are the standard garden variety.
He points out pinholes in the leaves of Regal Splendor, a white-margined, blue-green hosta. Someone nearby was spraying Roundup to control weeds and the wind drifted the chemical onto the hosta, he says, causing this minor damage.
"That's nothing; the plant will recover," he says, happy it's a plant he can keep.
Nearby, an unnamed hosta shows signs of crown rot caused by southern stem blight, a fungus called Sclerotium rolfsii. Too much water - "I have a well and dump it on," Hunyady says with a groan - promotes this scenario. Hostas like moisture, but they also need good drainage, he cautions, or you get all sorts of bad situations.
You know you've got southern blight when your plant collapses and there's nothing left but mushy leaf stems. You also see mustard-colored, seed-like balls of fungus. The cure is a fungicide called Terraclor 400 that you apply as a soil drench, according to the plant clinic at Virginia Tech in Blacksburg, Va.; the chemical is not widely available, so order it from a garden center.
Other things to be aware of
Then there's the reverse of too much moisture: not enough. If you wonder why a hosta develops severe tip burn, you can blame yourself for failing to make sure the plant gets enough water. This is especially true if the hosta grows in a pot off the ground or patio where air gets under and around the container, drying it out.
In addition to rots and blights, you may see microscopic worms called nematodes feeding on hostas. Look for yellowing that fills leaf tissue between the veins, he says.
He stoops to look at evidence of those worms feeding on Just So, a dwarf hosta.
"See how perfect it is up the vein," he says, removing a leaf for a closer look.
To test a plant for nematodes, remove a yellowing leaf and use scissors to cut off the tip end. Soak the leaf in a glass of warm water for about 30 minutes and you will see the barely visible worms swimming in the water. There is no control for this problem, so simply trim off the affected leaves and the plant will put out new ones.
Voles also like to eat Hunyady's hostas. To deter them, he fills 6-inch lengths of 1-inch-wide PVC pipe with blue waxylike mouse bait and drills a hole for attaching a flag that sticks above ground. He places the baited pipe in vole holes as soon as he spots them.
So far, that's one battle he's winning.