Pest control and new fertilizer may boost browning gardenia – Orlando Sentinel


Question. The buds of my gardenia are turning brown and the leaves are turning more yellow than green. I was told to apply an acid fertilizer. What else should I do?

Answer. Open one of the browning gardenia buds and you might find at least one of your problems. Most likely, tiny yellow to brown insects called thrips can be seen running around. These are very common in gardenia flowers and difficult to control when present in the buds. Next season, take control early with a natural insecticide containing spinosad. This insecticide can be found in the Bonide, Fertilome and Southern Ag product lines that are commonly found at independent garden centers. Ask a garden center employee to find one for you and follow the instructions on the label.

The second problem is probably nutritional. Acid fertilizer can help, but get one with slow release properties to apply once in March, May, August (if allowed) and early October. Additionally, the yellowing could be due to a magnesium deficiency. Try an Epson salt application using a product labeled for plants at the suggested rate.

Q I’m looking for the most durable bedding plants to last all summer. Which are the best?

A. My favorite plants for summer beds and containers are coleus and pentas. You can’t beat the color provided by foliage or flowers. Both are also long-term summer survivors tolerant of heat, humidity, and rains. They often last all fall and winter. But, I have to be fair to the other summer survivors and you can choose from alternanthera, also known as Joseph’s coat, angelonia, begonias, bush daisy, impatiens, melampodium, salvia perennial, torenia and zinnias at small flowers. On both lists, begonias, coleus, and impatiens grow best in shady areas of landscapes.

Q I understand that geraniums don’t like the summer weather, but my plants still look healthy and bloom. What can I do to keep them for another year?

A. Consistently hot, humid, and humid weather is the downfall of geraniums. Foliage begins to decline and plants rot. Yet many geraniums are kept for several years with heavy summer care. Find a place with good air circulation and sheltered from daily rains. Make sure the plants have sun and light conditions. Keep the soil moist but not wet and fertilize monthly to ensure your preserved plants arrive in October, when they will fully rejuvenate under normal growing conditions.

Q My lawn didn’t get fertilized this spring and now I’m being told I can’t apply fertilizer until the fall. What can I do to keep the lawn green?

A. Lawns may yellow a little but are unlikely to die without fertilizer during the summer. Check with your local University of Florida extension office, but most counties seem to allow minor nutrient applications that can often renew lawns’ green color. Also, put grass clippings back on the lawn while mowing, as they can decompose and release nutrients for growth. Finally, keep the lawn moist during dry periods so that the roots remain active and absorb the nutrients still available and those formed by the storms.

Q Our young shade tree has limbs that affect movement on the yard and sidewalk. Can we make the necessary cut at this time?

A. Don’t be in a rush to remove too many lower limbs as research indicates that the presence of limbs strengthens the trunks of young trees. Instead of removing the limbs completely, you can swing them backwards so they don’t affect those on sidewalks. Be careful not to leave stumps that could injure anyone who comes into contact with the tree. Gradually the lower limbs can be removed and the canopy raised above sidewalks, lawns and ornamental plantings. Any limb that could pose a danger to passers-by should definitely be removed. Eventually, limbs are normally held eight to ten feet above sidewalks.

Q I have lots of leaf lettuce but it is bitter. When it’s hot or the plants get bigger, does the taste change?

A. Plant size and temperature affect the taste and texture of lettuce. This is a cool season crop that is much milder in late fall, winter and early spring. Lettuce also develops the best taste and texture when growing rapidly. It is a crop to keep moist and fertilize to make the leaves grow tender and softer. It is now normal to get low quality tall plants with a bitter taste. Wait until October to plant your next lettuce.

Q We have a bird of paradise that has been healthy and growing for ten years but has never produced a flower. Is there an explanation for the lack of flowers?

A. You’ve been very patient, but now is the time to have a frank discussion with your plant. Tell her you are going to cut out the free food and put her on a low water diet. Most non-flowering bird of paradise plants quickly pick up on the idea.

It may seem like a bit of overkill, but only reduce watering during periods of severe drought. Also, continue feeding with light applications of a low-nitrogen bloom booster type fertilizer once in March, May and October. Make sure the plant has a full sun to light shade location and a 3 to 4 inch layer of mulch over the root system.

Sometimes we are just too nice to plants and they take advantage of us. Be tough and you could have flowers in a few months.

Tom MacCubbin is an Emeritus Urban Horticulturist with the University of Florida Cooperative Extension Service. Write: Orlando Sentinel, PO Box 2833, Orlando FL 32802. Email: Blog with Tom on


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