Ask Wendy
Weekly Home Horticulture Column
Spring 2004
- Bamboo
- Desert Rose
- English Dogwood
- Herbs
- Monarch Caterpillar
- Scale
- Sweet Potatoes
- Tomatoes
- Yellow Flies
May 2004
We are being so troubled by yellow flies that I can't even stay outside long enough to water my plants! Do you have any suggestions for coping with this pest?? (Lacrosse)
These yellow flies are very closely related to horse and deer flies. There are found in large numbers in Florida due to our mild climate and wet areas which provide good breeding sites for the pesky insects. Like mosquitoes, it is the female fly that is responsible for inflicting a painful bite. The males are mostly pollen and nectar feeders. The larva of the yellow flies live in moist soil or moist leaf litter, so if you are close to a river or a lake you are more likely to be bothered, than 
someone who lives in a drier area. The insects fly during the daylight hours, peaking in the hours around sunrise and sunset. The yellow flies will attack moving objects especially ones that are dark in color. They inflict a painful bite and take blood. There is really no control for large populations of the flies in nature. You can protect yourself by wearing long sleeve shirts and pants and or repellents such as DEET, citronella, or geraniol. Since they attack dark colors you should wear white or light colors. You can also make traps for small areas such as the back yard or pool area. Blue cylinders (5 gallon bucket painted blue) or large cups covered with tangle foot or another sticky material will help to trap them. Recent research has shown that blue inverted cups coated with tangle foot substance and attached to a slow moving (< 7 mile per hour) object like a lawn mower will be effective at reducing the abundance of these flies.
Large, fat, yellow caterpillars with black stripes around their circumference have striped the leaves from what I believe is butterfly weed (Asclepias tuberosa). Lots of neighbors have this same plant and theirs are covered with lush leaves and blooms. My two plants are now just sticks growing out of the soil. What can I do? (Gainesville )
You are successfully growing Monarch Caterpillar larva. This is the reason why many people plant milkweed also know as butterfly weed. In fact this is one of the few plants in the butterfly garden that serves double duty as a nectar plant for adult butterflies and a larval host plant for the hungry caterpillars. After the larva are finished eating the milkweed they will pupate and emerge as new monarchs. Your milkweed plant will recover quickly and regrow and look healthy again. The larva of the monarch is 1-3/4" to 2" long. It has colorful yellow, black and white rings that run the length of the body. Paired black filaments occur near the head and back end of the caterpillar. Larvae feed on milkweeds as well as dogbane. The monarch butterfly has a wingspan of 3-1/4" to 4" The base color of the wings is orange, with black wing veins and thick black marginal areas containing rows of white spots. The color of the upper surface of the wings is deep-orange; that of the undersurface is much paler. You might see another generation of monarch caterpillars this year, so if you would like to encourage them add a few more milkweeds to the butterfly garden.
We have scale on our small magnolia tree. Someone recommended a soap spray to help with this problem. How often should I apply this spray? (Newberry)
I agree with using a soft pesticide for Magnolia scale, especially if you do not have a severe infestation. You can use the soap type pesticide every 10-14 days or follow label instructions. It may be difficult to tell if the scale are dead and just remain on the leaves or if they are still active. To make sure you have control, wipe off the scale with a moist sponge or soft cloth.
When is the best time to plant sweet potatoes in the High Springs area? Also what type plant is best for the area and how do you suggest they be planted?
Sweet potatoes can be planted between the months of March and June; so there still is time left for you to get your sweet potato slips in the ground. Some of the varieties we recommend for north Florida are Porto Rico, jewel, Georgia red, centennial and sweet, the jewel variety is said to be resistant to sweet potato flea beetle. Start with certified transplants or slips. They will be ready to harvest in 120-140 days, and you can expect to yield 300 pounds from a one hundred foot row. Be sure to use thick stemmed slips that are 6-9 inches long. Thicker slips will have good food resources to help them take hold in the garden. Do not allow your slips to dry out too much before planting. The slips might look half dead when you purchase them, but with watering they often make it to be vigorous vines. One foot between plants and 4 feet between rows will give them ample of space to fill in and make plenty of potatoes. The sweet potato weevil can be a problem. This pest tunnels through the tuber making it inedible. To date there are no control measures for this insect, so try to use the resistant varieties and practice crop rotation so populations of the weevils do not increase. The growing season for the sweet potato is rather long at 4 months. They should definitely be harvested before the first frost and when the soil is not moist. If you plan on storing the tubers for a long time the will need to be cured in crates in a warm and humid area for 3-7 days. After they are done curing store the roots in a cool dry place.
Can you give me any tips for care of "Desert Rose" in this area? I purchased one after my trip to Kanapaha Gardens and can locate no info on how to take care of it. (Gainesville)
The desert rose (Adenium obesum) is a succulent plant that is native to eastern Africa and parts of Arabia. It is a favorite of many gardeners because it produces beautiful blooms with little to no care. It flowers best during the summer months in Florida, and the two inch trumpet like flower are seen in shades of pink, rose or white. The trumpet shaped flowers are very reminiscent to frangi pani blooms. The plant itself has very fleshy stems and a large fat bulb structure at the base of the plant. The bush will only get to 4-5 feet tall and is best kept in a pot in north Florida. Because of it short growth habit it often looks like a natural bonsai plant. It thrives at temperatures up to 90 degrees but it is not hardy to 40 degrees for many hours. Direct sunlight to bright sunlight is a must all year long, but be sure to protect the plant from the cold.
Water the plant as you would a succulent, letting the well drained soil go a little dry in between waterings. Increase the water when the plants are in flower, and reduce the water during the winter months. If your plants begin to shed leaves it may be due to over watering, so keep an eye out for leaf drops. In extreme cases, over watering will result in root rot disease and ultimately plant death. Scale and mealy bugs are insects that sometime occur on the leaves of the plant. Soap based insecticides will control these problems if you catch them early enough. The sap of the plant is an irritant so be care if you are doing pruning.
The best plants of the desert rose are grown from seeds since cuttings never really develop the interesting bulbous base that seedling grown plants have. This plant gets more interesting with age, so proper care will have your desert rose looking it's best for many years.
April 2004
A friend of mine would like to give me an English Dogwood. I don't know this plant. Should I accept the gift? (High Springs)
I definitely would accept the lovely shrub called English dogwood. It is also know as mock orange if it has a fragrant bloom. The scientific name is Philadelphus coronaries. This springtime bloomer is deciduous and grows best in a slightly shady site. It is very drought tolerant and can reach heights of 12 feet and can be as wide as 8 feet. It has a sprawling habit and is an interesting shrub to have in the landscape. The flowers of the plant, as everybody who grows it will tell you are worth the year wait. They are a bright white flower made up of 4 petals. The blooms can be greater than 1 inch in diameter, and the fragrance is wonderful. Their aroma will remind you of orange blossoms. Most of the shrubs that I have seen produce hundreds of flowers. It makes quite an impact in the garden.
This shrub will make small plants from the base of the mother plant which is why your friend wants to share with you. Plant it in a well drained area that is bright but doesn't get direct afternoon sun. You will need to prune it soon after it blooms since it produces flowers on the older wood. Some gardeners prune the lower branches to showcase the exfoliating bark that is on the lower framework of the plant. You will enjoy this gift, especially in the springtime.
Is the house plant "lucky bamboo" really bamboo? (Gainesville)
Lucky bamboo is a popular house plant that can be purchase in many different types of stores around town. It is actually a relative of the house plant called corn plant. Like its cousin the corn plant it does well in low light situations with minimum care. It is tropical in nature, so do not try to plant it outside. It would probably die the first time it got really cold.
I am thinking of planting a few more herbs in the garden this year. Do you have any suggestions? (High Springs)
Herbs are plants grown for their special flavor and aroma. Their ornamental attributes also make them an asset to the vegetable garden. The growing conditions required by herbs are usually the same as vegetables so incorporating them into the same bed makes perfect sense. Recommended herbs to plant in the spring garden are anise, basil, catnip, lemon balm, marjoram, mint, oregano, rosemary, sage, tarragon and thyme. I also suggest trying some of the locally available unusual herbs like cinnamon basil, burgundy basil, grapefruit mint or watercress. These can be found at the farmers markets or at local gardening stores.
I always have trouble with worms and insects in my tomatoes, is there anything I can do now to prevent this problem? (Gainesville )
The best thing you can do is to get an early start in the garden. We know that the pest pressure late (June) in the growing season can be very strong. You will begin seeing tomato fruit worms and horn worms devouring your plants and tomatoes the further into summer we go.
If you can get your plants up and growing well and producing fruit by May you will avoid many pests. You can do this by purchasing healthy plants or good seeds, growing the plants in plenty of sun; 6-8 hours minimum exposure, regular fertilizations, and keeping the soil that they grow in moist. By maximizing the cultural conditions you will have very healthy plants that will not be prone to diseases or insect attack. Use the principles of IPM to keep insects and diseases in check. Exclude diseases and pests from the garden by purchasing and using only disease free plants. Eradicate pests and diseases by practicing crop and site rotation. Remove diseased plants or plant parts as soon as you see a problem. Purchase varieties that are resistant to diseases and keep the plants healthy so they can resist attack. Protect your tomato plants by beginning control efforts early with bio-rational products such as Dipel for caterpillars, insecticidal soaps for aphids or white flies, and rotenone for beetles or grasshoppers.
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