Q. Bill writes: When I moved to Florida last year I planted a Mandevilla and allamanda. The tags said full or partial sun so I planted them on the east side of the house. I now have good vines but no flowers. Are they getting enough sun?
A. Most likely you have diagnosed your own problem - the plants need more sun. They are really full sun plants but can survive in filtered sun and still produce some blooms. The half day of sun is just not enough and you should give them a new location.
Q. Mary Sue writes: I have more acorns in my yard than any other year I can remember. Why and can the acorns damage the soil? I don't want an oak forest either.
A. Your trees are certainly going to make a lot of squirrels happy as they help harvest the crop. The extra heavy production is due to several years of good growing conditions. Even with the dry spring weather the trees set and held the acorns using foods stored in the trunk from previous years.
If the squirrels, insects and other small animals have their way it's doubtful many good seeds are going to be left to sprout new trees. If needed seedlings can be pull or mowed down to prevent an oak forest. The decomposing acorns do return nutrients to the soil to help feed the tree and nearby turf.
Q. Dee Dee writes: Our sago plant is full of bright orange seeds. When are they harvested and what treatment is needed to start new plants?
A. Sago seed are ready to harvest. There are many ways to process the seeds but the simplest technique is to place them in the refrigerator where they continue to mature.
Place the seeds in a food storage bag to which several holes have been added. Leave them in the vegetable section of the refrigerator for 120 days. During this time the embryo continues to develop and the seeds swell and often crack.
After the cold treatment remove the seeds from the bag and rub off the other orange covering. Sow the seeds in a shallow container filled with a potting soil mix. Push the seeds half their thickness into the soil and water to begin the germination process. Most should begin to sprout within a month.
Q. Alex writes: I want to put in a new bahia lawn. I plan to apply a herbicide to destroy the old grass and weeds. After it turns brown does the old lawn have to be removed before the new grass is installed?
A. Current University of Florida recommendations suggest a complete renovation of the planting site before adding the new sod. This includes controlling the persistent weeds and tilling the soil. Old plant portions should be raked from the soil and the ground leveled before planting.
Some gardeners do take a chance and mow the old turf close to the ground and then add new sod. This can result in poor root growth and an inferior lawn.
Q. Jon writes: I am trying to establish a lawn in an area once planted with junipers. The area has several large deciduous trees and a few pines. What type of turf should I use?
A. The landscape sounds more suitable for a shade loving ground cover than turf. You might consider either Asiatic jasmine, English ivy, mondo grass or wedelia as an alternative to turf grass if the spot has more than twenty-five percent shade.
Where you have lots of filtered sun or sun for major portions of the day you can plant one of the shade tolerant St. Augustines. Varieties to choose from include Amerishade, Bitterblue, Delmar, Palmetto and Seville.
Q. Cindy writes: Something is eating holes in my zinnia leaves and I think it's snails. I have been using an insect spray and it seems to help a little. What else can I do?
A. One of the best controls is picking the snails off the foliage during the early morning or evening hours. Another control is to scatter snail and slug bait over the surface of the soil under the plants late in the afternoon following label instructions.
As you have noted commonly used insecticides have very little affect on these plant pests.
Q. Wilbur writes: Chinch bugs have damaged spots in our St. Augustine lawn but are under control. What do I do with all the dead grass? Should the dead areas be resodded or will neighboring St. Augustine fill in the bare spots?
A. It's best to fill in large dead areas with sod or plugs of St. Augustine turf during the fall months. If left open weeds may become established to compete with the healthy grass.
Rake or dig out the dead sections and loosen the soil before adding the new grass. Keep the soil moist and apply a fall feeding three weeks after adding the sod or plugs. Mow the new turf as needed at the recommended height for the variety selected.
Q. Mike writes: I have tried to root viburnum cuttings in both soil and water and have failed each time to obtain new plants. What am I doing wrong?
A. Some plants do not root well in water. Also soil contains organisms that may cause plant stems to rot rather than produce roots. Try rooting your cuttings in vermiculite a type of clay available from garden centers.
Fill a large pot with vermiculite and moisten to hold the cuttings. Take tip cuttings 4- to 6-inches long to root. Dust the cut ends with rooting powder and stick the ends about two inches deep into the vermiculite.
Keep the cuttings in a shady location and mist several times a day. Most gardeners like to surround the containers of cutting with plastic to increase the humidity. Viburnum cuttings root in 10 to 12 weeks during the warmer weather and can then be transplanted to individual containers.
Q. Jill writes: I have a bromeliad plant with a red bloom that's fading to a tan color. Should I cut the flowers off? What happens to the plant?
A. Colorful bromeliad portions are a combination of flowers plus foliage collectively call an inflorescence. The inflorescence can last for months then gradually declines. Enjoy the color until it begins to fade then cut the flowering stem from the plant.
After flowering the mother plant gradually declines. The fading of the green leaves to brown may take several months to a year. Usually several new plants form at the base of the old plant and often conceal the declining portions. You can remove the old plant or leave it among the new green stems.
Q. Matthew writes: Our landscape has a number of colorful crotons I would like to share with friends. How do I root the stems to start new plants?
A. Start small stem portions rooting in vermiculite. Make the cuttings 4- to -6 inches long and remove a few of the older leaves. Dip the cut ends in rooting powder.
Fill a shallow container with vermiculite and dampen. Stick the cut ends of the croton stems an inch or two deep in to the vermiculite. Set the container of cuttings in a shady location and thoroughly moisten.
Many gardeners like to surround the cuttings with a plastic cover to further hold in moisture that speeds rooting. Continue to keep the croton foliage and vermiculite moist and the cuttings should root within 12 weeks and be ready for potting.
Q. Chester writes: I am wandering what the wasp shaped bugs are around my crape myrtles. Should I ignore them or worry about them?
A. Wasps do fly in to collect insects to add to their nests that feed hatching eggs. They are beneficial insects that help control caterpillars and similar plant feeding pests. Wasps also get some water and sap from plants. There is no need to control the wasps but gardeners allergic to the sting should realize the insects are frequent landscape visitors .
Q. Phyllis writes: A large gardenia bush has slowly declined to barren twigs and branches. It's received good care including frequent feedings and sprays to remove sooty mold. . What might have caused the decline?
A. Gardenias need lots of attention. Besides the frequent feedings the plants also like a moist soil. Excessive drying can cause a gardenias do quickly decline. To help hold in the moisture add a 3- to 4-inch layer of mulch over the root system.
You indicated a spray was applied to remove sooty mold but did it control the insects? Scale, whitefly and similar piercing sucking insects rob gardenias of vigor. Most likely the pests continued to feed and caused the bush to decline. Gardeners can use oil sprays to control these pests but often have to make repeat applications throughout the year.