Residential Lawn & Garden

Roses FAQs

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What's the matter with my roses? Many leaves are turning yellow and dropping off.

Lower leaves: Natural attrition from age and maturity, sometimes triggered by heavy rains, excessive watering, or a sudden change in weather conditions. Heavy infestation of spider mites. Spray burn from frequent spraying with insecticides. Upper leaves: Fungus disease, usually blackspot. Gardeners sometimes do not note the characteristic spots, only that the leaves are yellowing and dropping. If the problem is blackspot disease, start spraying every week or 10 days with a recommended fungicide. Successful rose grower's alternate between 2 or 3 fungicides. Pick off all the affected leaves you see and dispose of them. Clean up any you see on the ground. Blackspot is spread by splashing rain or irrigation and thrives when the leaves stay wet for more than 6 hours. It helps to keep foliage dry by using drip or micro-spray irrigation. Blackspot fungus is a "fact of life" for roses in Florida. Only the Old Garden Roses (also called Antique Roses) show significant resistance.

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The new growth and flower buds on my roses are covered with white mold. Some of the buds and new leaves are twisted and distorted. What's wrong and what can we do about it?

The problem is powdery mildew disease. The affected growth cannot recover so trim it off and discard. Then spray with a fungicides labeled for this problem. Ask your garden center professional or Cooperative Extension Service for recommended products. Be sure to cover new growth thoroughly.

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Something is chewing round holes in my rose leaves. I've looked carefully, but can't find a caterpillar or anything that could be doing it.

Leaf cutter bees cut out perfect, little circles of rose leaves to line their nests. Spraying is useless because this insect does not eat the leaf, only uses it as nesting material. Damage is merely aesthetic and does not harm the health of the plant.

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I want to plant a small rose garden. How far apart do I space the plants?

Roses in Florida, planted in a bed, should be placed at least 4 to 5 feet apart, no more than two plants deep, so that they may be reached for care on either side. The growing season is very long and healthy plants attain very large size in the course of a year.

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How much and when should you prune?

First year plants should be trimmed very lightly mainly to clean out twiggy, unproductive growth. A certain amount of pruning is done all through the year every time a bloom is cut. Any dead or unhealthy canes should be removed immediately as soon as they are seen. Clean sharp clippers are a must. Major pruning of mature rose bushes is done in Central Florida from mid-January to mid-February. Old and damaged canes are removed cleanly at their base to encourage new growth and improve air circulation. Those left form the framework of the next year's growth. Shorten each cane by 1/3 to 1/2 depending on the height and growth habit of the variety. Remove all foliage.

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My plants look healthy but the blooms are brownish and some buds don't even open.

The problem is flower thrips, very tiny insects that attack the buds and new growth. They are worse in spring, but will continue into summer and fall in some areas. Thrips invade the buds just as the sepals separate to show color and once inside are almost impossible to kill. Spray a systemic insecticide on the flower buds and new growth. Repeat sprays at frequent intervals as long as infestations are serious.

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Our roses look terrible, The leaves looked bleached, some have a spidery webbing and some are dropping. We spray and spray but it doesn't help. What can we do?

Spider mites are one of the most serious pest problems on southern roses. In hot, dry weather they multiply explosively, feeding on the moisture in the leaves and stems and causing defoliation and weakening of the plant. One preventive treatment is to regularly drench the leaf undersides with a strong jet of plain water. If pesticides are used, make sure they are labeled for spider mites and follow directions carefully.

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How should I take care of my roses?

Roses need at least 1 to 2 inches of water a week during hot, dry weather. Water in the early morning so that the foliage will dry quickly. A good rose fertilizer or a premium lawn fertilizer (one with a 16-4-8 analysis) should be used. Look for one that contains slow release nitrogen and is low in chlorine - no more than 5%. Apply one cup per month, as the plant grows larger. Water well before and after fertilizing. Have a pH test at least once a year and follow the recommendations as to whether or not to apply lime. Roses grow well between 5.5 and 7.0, but do best between 6.0 and 6.5. Keep blooms trimmed off to encourage more flowers. Cut the flower stems just above a 5-leaflet leaf, making sure at least two 5-leaflet leaves remain on the stem you have cut from.

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What are the best types of roses for Florida?

"Old Garden Roses" (also called Antique Roses) are the easiest to grow and the most resistant to disease. Hybrid Tea varieties should be container-grown and grafted preferably on "Fortuniana" rootstock (Dr. Huey is the next best). Container-grown roses can be planted at any time of the year as long as as they are well watered and cared for.

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Is there any special way I should prepare the bed before I plant the roses?

After clearing out all grass and weeds the soil should be amended with as much organic material as possible. If practical the bed should be raised 8 to 12 inches to provide better drainage. If the area is poorly drained the base should be dug out first before amendments are added. A pH test to determine soil alkalinity or acidity should be made to find whether lime should be added and if so how much. Dehydrated manure, spaghum peat moss, compost or commercial bed mix are all good materials to incorporate into the planting bed. Many rose grower's also add bone meal or super phosphate in small amounts. The prepared bed (or separate planting holes) should be well watered and allowed to settle before planting. After planting the young plants should be staked to protect the ender grafts from sudden wind storms and then heavily mulched with organic mulch such as pine needles, oak leaves, or bark. Avoid inorganic mulches such as river rock - the excessive heat generated on bright summer days can be disastrous for young tender surface roots.

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