Answer: This rusty appearance is caused by a fungus called red spot. The organism produces spores within the discolored areas that blow away or wash away other plant parts and initiate new infections. Most amaryllis and carnations in local landscapes appear to be affected by the red spot fungus.
Fungi are difficult to control. Start by removing severely damaged foliage and old leaves that have fallen to the ground. If necessary, systemic fungicides Thiomyl or Halts can be used to help reduce the disease; Follow label instructions. Repeated applications are usually needed to be effective. Most gardeners ignore the disease unless plant vigor is affected.
Mushroom traditions, facts
Q: Mushrooms have been forming in our garden. Is there good control?
A: Mushrooms grow in the organic matter in your soil. Folklore suggests that this was an area where fairies danced on the grass all night. But we do know that the growth is caused by one or more fungi that thrive during warm, moist weather.
New fungicides are available, but they are difficult to find and relatively expensive when compared to what is typically found on the garden center shelf. These products include ProStar and Heritage.
One option is to collect mushrooms and throw them on the compost pile. Composting will destroy the germs. Or you might leave it on the grass to wither, if you believe another bit of folklore that mushrooms mark the place where the devil mixes his froth.
Lily of the Nile can be transplanted
Q: My agapanthus has flowered. Should I wait until the flower stems die back to transplant it into a larger container?
A: Your plants are ready to plant at any time. You can remove the seed stalks unless you want to produce seeds to start more agapanthus, also known as the lily of the Nile. Then give the plants a pot that is 1 to 2 inches larger in diameter. Use loose potting soil when filling containers.
Crepe myrtle hedge
Q: I have 20 crape myrtle plants that I was told would form bushes. They get about four hours of sun. How far should it be planted to create a hedge?
A: Crape myrtle shrubs can grow to 15 feet tall and 10 feet wide. A spacing of 6 to 8 feet would be ideal, allowing the branches to intertwine at maturity to form a barrier. Crape plants do not form a dense hedge. They lose their leaves for the winter.
The main concern is the amount of light your plants receive. Crape myrtle plants grow best in full sun. Plants that receive only four hours of direct sun per day are more likely to produce skinny buds and flower poorly.
Spiders bite tomatoes
Q: Tomatoes have a kind of web, and the leaves turn yellow. What can I do to eliminate the problem?
A: Spider mites feed among tomato plants. These are small arachnids that suck juice from stems and leaves. By the time the webs are observed, large populations have built up and the mites are out of control. Look closely and you’ll be able to see thousands of minute-sized mites covering the leaves and stems.
The best control now is to remove infected plants from the garden to prevent the infestation from spreading to nearby tomatoes. Plants with minor infestations can be treated with soap spray, available at local garden centers; Follow label instructions. Frequent spraying is usually needed throughout the growing season.
Delayed movement of camellia
Q: We have two camellias that we would like to transplant. Do we prune it and what is the best time to plant?
A: If possible, delay moving until a cooler time of the year. November through February is usually an ideal time to plant, when plants are less active and moisture loss from foliage is minimal. New research suggests that it’s best to leave as much stems and foliage on the plant as possible. Hormones produced at the ends of branches appear to encourage new root formation and better plant growth.
Azaleas dry up
Q: I have azalea plants that are about 6 months old and their leaves are turning brown and appear to be dying. What could the problem be?
A: The root balls of your transplants most likely dried out during the spring and early summer months. Once dry, root systems are difficult to rehydrate and plants decline. Dig down to check the root balls to make sure they are moist.
If the soil is dry, create a berm at the edge of the root ball and fill with water. Moisture must penetrate the soil. Moisten every two to four days until the plants begin to grow. Azaleas are slow to develop new roots and need constant attention to moisture needs for two or more years.