Garden Q&A: You'll have to be patient to find impatiens again

My impatiens are losing their leaves and dying back. I was going to replace them, but I can't even find impatiens in the nurseries. What's going on?

Impatiens have always been our go-to plants for shade, flowering through the heat and downpours from late spring until frost. Last fall, a downy mildew disease showed up in Florida and wrecked our happy partnership. It is airborne, spreads rapidly, can't be prevented and can't be cured. So most commercial growers did not grow impatiens this spring and therefore plants are rarely available.

There are quite a few other plants that will do well in a partially shaded area. County agent Terry DelValle recommended wax begonias, hardy bromeliads, coleus, crossandra, firespike (Odontonema cuspidate), jacobinia, leopard plant, peacock ginger, Persian shield, torenia and walking iris. The firespike, jacobinia, Persian shield and walking iris get to be a bit tall, but the others are fairly compact. I would add one of my favorites, the dragon wing begonias, as well as other ginger plants.

Over the next couple of years, you can be sure that researchers and hybrid seed developers will be searching out mildew-resistant varieties of impatiens. Once they develop them, we will have them back on the market.

The lorapetalum and holly hedges we have are dying one by one. What would cause that?

Both are hardy plants. But like most plants, they are susceptible to root problems caused by deep drought alternated with excessive water. Lorapetalum, in particular, is drought tolerant. When it gets too much water, it becomes stressed and diseased. The popular variety "Ruby" has been suffering from a decline in Central Florida. The variety "Plum" is more resistant.

Hollies require a little more water than lorapetalum, but they are also considered to be drought tolerant once they are well established.

Can you recommend some trailing plants for our containers?

In addition to the sweet potato vine (chartreuse, purple and variegated versions available), you can use vinca vine, alternanthera dentate, Million Bells, Heliochrysum (Note: this plant will crash and die when fall rains become heavy, but is lovely with its fuzzy gray leaves until then), purple heart, ivies and creeping fig all make nice spillers from containers.

Along with thrillers (dramatic upright plants) and fillers (smaller flowering plants), spillers (those plants that trail over the sides) make for a well-designed container.

I have an oak tree that is covered with spider web. Is it doing damage? What can I spray on it?

This question comes in at least once a year. The small critters that make this webbing are called Psocids, or tree cattle. They move from tree to tree (one wonders how), cleaning up bits of algae and decaying plant matter that get trapped in the bark crevices.

They do no harm and may be beneficial. They are called tree cattle because if you tap your finger in front of them they will "stampede" in the opposite direction. Then, if you tap your finger in front of their new direction, they will turn as one and stampede in a different direction.

They are just one of nature's interesting oddities.

My veggies are doing fine, but I'm wondering what to plant next month when they are finished. This is my first year growing vegetables.

You could grow some heat-loving plants like eggplant, okra, Southern peas or peppers.

But you would be better served to just rest your garden bed.

Taking a break in the hottest, wettest part of summer gives the veggie pests a challenge. With no plants to prey on, they may not be able to reproduce. Growing through the summer increases the number of pests around when the fall garden is planted.

The next three months are a great time to clean out the vegetable garden and equipment, plan your fall/winter garden, and start seeds for the cooler season.

Download a copy of the University of Florida's Vegetable Gardening Guide to get all the best dates and the best varieties for our climate: edis.ifas.ufl.edu/vh021.

Becky Wern is a master gardener with the Duval County Extension Service and the University of Florida/IFAS.