Question. All of a sudden, our plumeria has developed yellow leaves with an orange coating on their backsides. What should I do to control the decline?
Answer. Many of our favorite flowering plants are susceptible to a disease called rust. Besides the plumeria — also known as the frangipani and the lei flower — hollyhocks and cannas are also affected. The decline noted is caused by a fungus that flourishes during warm to hot, damp weather. During dry times, rust is seldom noticed. As you observed, the leaves yellow and masses of orange spores form on their lower surface. Normally gardeners apply a fungicide as soon as the leaf decline with orange spores are noted. Several fungicides are available at garden centers that list rust control on the label to treat the disease. Repeat sprays are likely to be needed during moist weather following label instructions. Since your plumeria is being affected so late in the season and leaves are going to drop for the winter, sprays are likely to be of little value until late spring when the disease returns. Do gather and dispose of the affected leaves.
Q. I am planning to create hanging baskets of petunias in former containers. The baskets are about twelve inches in diameter. How many petunias do I need?
A. Most likely, you are trying to stretch your gardening dollars as the price of all plants, soil and containers has risen over the last few years. If you want to really save money, place one petunia in the center of each hanging basket filled with fresh potting soil. With good watering and fertilizing practices, it can gradually fill the container with foliage and flowers. Obtain a quicker basket of color, but at triple the cost by using three petunias spaced an inch or two from the edge around the container. With three plants, you can add more than one color to the hanging baskets.
Q. We try to grow beets but have not been successful. What is the secret?
A. A beet crop is in your future if you start the seed during the cooler weather. November and December are great months to make the plantings. Beets are sold in packets of small capsules that contain several seeds each. Plant the capsules in a prepared garden site about an inch apart. Cover with up to a quarter inch of soil and keep moist. The seeds should germinate within seven to ten days. Notice clusters of beet plants usually sprout from the capsules. You may need to thin the plants as they grow older to one plant every inch or two. Keep moist and fertilize monthly for a crop to pull and eat tops and roots in about 90 days.
Q. We are planting a new landscape. What are the important steps when adding new shrubs?
A. Start the planting by making sure the root balls are thoroughly moist. This may mean setting the plants still in their pots in containers of water for a few minutes. Next, dig a hole for the new shrubs that is wider but no deeper than the root ball. It would be best if the hole were not quite as deep as the root ball so the top can be set an inch or two above ground level. Then, set the plants in their holes and fill them with soil. Add a two to four-inch berm of soil at the edge of the root ball. Use this to direct water down through the root ball. Water daily the first week or two and every two to three days during the drier months through spring.
Q. Our sago has dark green leaves at first, but then they turn brown. We have applied palm food and magnesium. What can we do?
A. Browning of new sago leaves does suggest a nutrient deficiency. But it’s usually a lack of manganese that causes the plant to decline. You have applied a general palm fertilizer that may contain some manganese but probably not enough to correct a deficiency. You have also applied magnesium, which is often confused with manganese. Give the plant a manganese sulfate application following label instructions. One application is all that is needed. New growth produced a month or more after treatment normally continues the good green color.
Q. Now that the crape myrtles have stopped flowering, is it safe to trim the branches to the desired height? Will winter affect these trees?
A. Winter damage is likely to occur if you prune the crape myrtles at this time. The tree forms and shrubs need a rest period, often referred to as dormancy. This is the way they prepare for spring growth and resist cold damage. If crape myrtles are pruned during fall, they are likely to sprout new shoots and continue growth into the winter. This makes them more susceptible to freezing temperatures. Similar damage may occur if the trees are growing under nighttime lights that keep them in a growth phase. Wait until January or February to do major pruning. Of course, a shoot that is in your way can be removed at any time.
Q. I purchased several pumpkins at a local market and would like to keep the seeds to grow more plants. What should I do, and when are pumpkins planted?
A. Pumpkins are fun to grow for more than jack-o-lanterns. The seeds are kind of sticky, so remove them from the center of the pumpkins and wash them off a little. Then, place them on wax paper or aluminum foil to dry indoors out of the sun. After drying for a day or two, place them in a jar or plastic bag and store them in the refrigerator. The next planting time for pumpkins is March. The crop needs about 100 days to produce a ready-to-use fruit. The biggest problems are leaf spots and caterpillars, so keep the sprays handy. They should also be fed lightly once a month with a general garden fertilizer. Pumpkins can be planted again in July or August to have some available for Halloween or fall dishes.
Tom MacCubbin is an urban horticulturist emeritus with the University of Florida Cooperative Extension Service. Write him: Orlando Sentinel, P.O. Box 2833, Orlando, FL. 32802. Email: TomMac1996@aol.com.
