SHRUBS - FLOWERING
Q. What are some good flowering shrubs to put in my yard?
A. Good flowering shrubs include the large 10'-12' Cape honeysuckle and golden dewdrop. Cape honeysuckle has orange flowers in winter. Golden dewdrop has blue flowers and blooms much of the year. It also gets orange berries that attract birds. Plumbago is a blue flowering smaller shrub to 6'. Hibiscus, `Nora Grant' ixora, pinwheel jasmine, and thryallis are all good, long-blooming shrubs that you might try for an extended flower display. Stay away from oleander (constant caterpillars) and most ixora (nutritional problems and cold damage) in particular.
Q. What are some suggestions for planting flowering shrubs on the north side of our condo?
A. The north side is shady so your plant list is somewhat limited. Most flowering plants need sun to bloom well. If the north side of your condo has no trees in the area you will be able to grow a larger variety of flowering shrubs. Under windows, where you do not want a plant taller than 3 feet or so, I would recommend crossandra, which has orange flowers over the warmer part of the year and grows to about 2 ½ feet tall, or Indian hawthorn which grows to 3 feet, has dark foliage and small white flowers. This is the best low shrub for long term performance. There are pink forms from California that sometimes show up on the market. Brazilian plume flower (Justicia cornea) is another short shrub, around 24 inches that blooms well through the summer. All of these plants can be spaced about 18 inches apart. Taller shade lovers include blue sage, which grows 5-6 feet and has pretty blue flowers from December through March. In early April, prune the old flower clusters. Clock bush is a good plant for light shade. It reaches about 7 feet and has beautiful purple trumpet type blooms in spring and winter. Thryallis or shower of gold will bloom in light shade. It has yellow flowers 10 months of the year (rests in January and February) and reaches about 7 feet tall. Crape jasmine has a double and single form available. It is an acid lover, so plant it out from the foundation. The double form is the most available and can reach 8-10 feet in height. It is a faster grower than the single form. Use an azalea/gardenia fertilizer to keep the deep green leaf color. The white flowers occur in spring and summer on the double form. I like the pinwheel jasmine, the single form best. This plant blooms all year and is very slow growing to 6-8 feet. I think it is one of the best plants for sun or shade.
Q. My pinwheel plants have yellow leaves and only a few flowers. They have no new growth. Can they be saved?
A. The pinwheel jasmine is a beautiful plant if well grown. Like gardenia, ixora, hibiscus, ligustrum and orange jessamine, it is an acid-loving plant. It should be planted away from concrete sidewalks, pool decks and house foundations. It is very subject to chlorosis from high pH. Fertilize with an ixora/gardenia fertilizer. It likes sun to partial shade. Make sure the plant is planted at the same depth it was in the original container. Planting too deep can cause the plant to die back.
Q. I need a startling, upright, compact plant for a northern corner of our building that receives only a few hours of sun a day.
A. I would use a colorful foliage plant for a corner location with sparse light. The caricature plant, Grapophyllum pictum, comes in a yellow and green leafed form with pretty flowers. The chenille plant, Acalypa hispida, has red drooping cattail flowers most of the year and is a conversation piece. The copperleaf, Acalypha wilkesiana, has variable-colored leaves, but the red form is the brightest. It sometimes defoliates if the winter is cold for these plants.
Q. Can I grow azaleas in South Florida?
A. Azaleas can be grown here with some difficulty. Generally the further north you are in south Florida, the better luck you will have. Azaleas are acid loving plants and south Florida soil is mostly alkaline. Keep them in the shade. If you have live oaks or slash pine on your property, they will grow well under them. Do not plant them near any cement and do not plant too deeply. They have a shallow fibrous root system and dry out quickly, so watch plants for wilting. They benefit from mulching to retain moisture. Use about 50% peat moss well mixed with existing soil when you plant. Fertilize in March, June and October with azalea/gardenia fertilizer. The best varieties for south Florida are: `Red Wing', a low to medium grower with red flowers; `Formosa', a tall growing plant with purple flowers; and `Sweet Surrender', a Formosan type with good alkaline soil tolerance.
Q. I have azaleas in all colors and notice the leaves are small. Do they grow tall so that I will have to trim them?
A. Azaleas that get too much sun may have small leaves. Kurume varieties grow about 3 feet tall; Indica types grow 6-8 feet tall. Prune right after flowering for best results
Q. My gardenia has black stuff on the leaves and is dying. What is wrong?
A. Sucking insects are attacking your plant. Apply Orthene to the plant according to label directions before 10 a.m. Repeat spray in seven to ten days.
Q. One part of my gardenia is dying. Is it trunk die back? I have sprayed with insecticides and use gardenia fertilizer.
A. Your gardenia could have graft incompatibility, which would cause a branch to die back. There is no cure.
Q. My gardenia has bloomed nicely and now it is putting out long branches since repotting. Should I cut these off?
A. Your potted gardenia is probably gardenia `Radicans', a ground cover also known as the dwarf gardenia. Allow the long branches to develop for more flowers.
|Q. I need to find an early blooming
gardenia variety as I want to enjoy the flowers all year.
A. The small `veitchii' variety would be a good one to try. It only grows to 4 feet or so and blooms on and off through the year. The flowers are smaller but the fragrance is as good as the big growers. The big variety `Miami Supreme' will sometimes bloom in the winter as well but will make a bush over 8 feet tall and across. Most nurseries should be able to special order for you. A good gardenia specialty wholesale grower is Carroll's nursery in Clearwater Fl. 1-813-535-5888. Most nurseries order their gardenias for spring sales.
Q. I've seen hydrangeas in the supermarkets. Can they be grown near the ocean?
A. Hydrangeas do grow right on the ocean. I have seen them in these locations in Delaware, Cape Cod and Nantucket. The hydrangea will grow in northern Florida, but we do not have enough cold weather for success here. Plants have a northern and southern limit, and hydrangeas range from southern New England to northern Florida in hardiness. You might try Dombeya X `Seminole' which blooms over the winter and has some resemblance to a hydrangea. Tropical World, a wholesaler in Boynton Beach had them. Have your landscaper or retail nurseryman call about availability for you. My plant blooms from November through April with pinkish-red flower clusters.
Q. I see a lot of hibiscus in South Florida. Is it because they are so easy to grow and are problem free?
A. Most hibiscus are from the Pacific Islands and the Orient. I strongly suspect that the insects that pollinate them in their native lands are not present here. The plant is reproduced here artificially by cuttings and could propagate naturally by layering although this is unlikely because of the upright growth habit. Hibiscus breeders use hand pollination for cross breeding to create the beautiful flowers and colors we see at the hibiscus shows.
Q. I bought a hybrid hibiscus at a show and it hasn't bloomed. Why?
A. Your hybrid hibiscus will bloom with time. Show hybrid hibiscus are often shy bloomers when compared with the old-fashioned single red forms which are in bloom almost daily. The huge flowers on some of the hybrids are up to 7 or 8 inches across and take a lot of energy to produce. Be patient. The blossoms are worth the wait!
Q. When do I transplant hibiscus?
A. Hibiscus can be transplanted any time as long as plenty of water is available. Plant them in the ground. Potted plants require a lot more work.
Q. Can I grow Rose of Sharon as a privacy hedge?
A. Rose of Sharon is a relative of our hibiscus. I have seen plants here in the ground. They will do reasonably well here although we are somewhat south of their preferred range. Rose of Sharon will tolerate sun to partial shade. It is a large grower to 12 -15 feet tall, so allow plenty of room for its growth. The plant has a growth habit reminiscent of a small tree and tends to be bare at the base, so I wouldn't use it for a privacy hedge.
Q. I want to tell you that the yesterday-today-and-tomorrow plant causes shortness of breath, congestion, wheezing and rhinitis. It has a cloying sweet odor that fills the air. You must stay inside or leave the area. Warn your readers.
A. I think yesterday-today-and-tomorrow is getting a bad rap. It is not fragrant; I have a plant in my yard, and I'm allergy-sensitive. I strongly suspect that the night-blooming jasaine, melaleuca, mango, Brazilian pepper, vitex, angels's trumpet, day jasmine or chalice vine may be in your vicinity. These are the main allergy producers in Florida.
Q. The maintenance company hacked back our oleanders to sticks when they were in full bloom.
A. I would not prune oleanders because they are subject to bacterial gall, a fatal disease that is spread from plant to plant by pruning shears. If pruning is done on bacterial gall infested plants, it can be spread to infect other oleanders on the property. Bacterial gall shows up as swellings on the stems and dead shoots above. You must dip pruning tools in alcohol between each cut. The oleander is woody in nature and does not regenerate well from repeated cuttings. It naturally is bare of foliage at the base so it is best to let it grow naturally as a background shrub and plant something low in front. Oleanders attract caterpillars, scale and gall. They should be used far away from buildings so the flowers can be observed at a distance and their faults will not be so obvious.
Q. How do I root a plant like oleander?
A. Oleanders can be rooted from cuttings cut at a diagonal across the stem. The cuttings are branch tips about 4-6 inches long. Strip the bottom leaves off the cuttings and dip the ends of the cuttings into a rooting hormone like Rootone. Put the cutting in a light potting soil mix or half sand and half peat moss mix. Put the plants on the north side of the house or under a tree where the direct sun does not hit them. Keep cuttings moist but not soggy. They should root as new plants within two to three months. Then gradually move them into more sun. Eventually you can plant them into the ground after five or six months when they are well rooted.
Q. I am looking for something with blue blossoms and easy care to plant in my yard.
A. Plumbago is one of the subtopic's few blues. It requires little care. It likes sun to filtered shade. Water established plants one to two times a week if there is no rain. Plumbago can spread about 5-6 feet over time. New leggy shoots lean over, branch and flower, so do not cut them off and it will spread .
Q. I have a large stand of plumbago about 20 years old. They give off fewer and fewer flowers. What fertilizer and water do they need? Can I cut them back drastically?
A. Plumbago does well with an ixora/gardenia fertilizer applied in March, June, and October. Do not cut them back drastically unless it is absolutely necessary. When I had my house painted, I cut my plumbago to the ground to provide access for the painter. The plumbago is now 6 feet tall and looks fine. However, this radical pruning would not normally be recommended on most plants. Plumbago has the ability to come back from the roots with few problems, so it worked in my case. In most instances, I would only remove a third of the total growth. Remove dead or old wood to let new growth renew the plant. June or July is the best time for heavy pruning as the plant has cloud cover to protect it from sunscald and it will recover quicker in the summer months.
Q. Will butterfly bush and lemon grass grow in Palm Beach County?
A. Butterfly bush and lemon grass do grow here.
Q. I planted some dwarf ixoras in front of my house and they died in two months. I would like another suggestion on what to use. I thought arborvitae or the yews from the north as possible replacements. Can yews grow here?
A. Stay away from arborvitae as they age poorly here and can get to be 25 feet tall and as wide. Yews will not grow here as we are too far south. The big pink `Nora Grant,' `Super King' and Ixora coccinea varieties normally do not have flowering problems if they receive at least 4-5 hours of direct sun. I find the dwarf ixora troublesome as they are subject to nematodes and get chlorotic. Plant any new plantings out beyond the drip line of the roof. Space big ixoras 2 to 2 ½ feet apart and smaller plants 1 ½ feet apart. Remember that flowering plants bloom at the ends of the branches so cut only off extra tall shoots so you do not ruin your flower display. Keep the acid-loving ixoras away from alkaline concrete sidewalks and buildings because this causes a great deal of stress on the plants. The concrete's alkalinity leaches into the nearby soil as the building or walkway weathers. Our soils are generally alkaline to begin with so the concrete intensifies the problem. They will need an acid fertilizer in March, June and October.
Q. I have brown leaves on my `Maui' ixora. Is that leaf spot?
A. Fungal leaf spot indicates your plant received too much water or that water was applied at the wrong time. Water only between 2 and 10 a.m. to minimize fungal problems. Copper fungicide is used to control leafspot. `Maui' ixora can be attacked by microscopic worms called nematodes, which can cause leaves to brown off and look bad. `Maui' only last three to four years because the nematodes kill them. Do not replace them with other `Maui' ixora.
Q. The leaves on my ixora are covered with a black mold. What do I do to clean them?
A. Your ixora has sooty mold, a fungal by-product growing on the oneydew created by sucking insects. The sucking insects are most likely scale or mealybug. Try soapy water _ two teaspoons of liquid dishwashing soap to a gallon of water. Spray the mixture on the affected area, particularly along the stems and on the undersides of leaves. Repeat weekly for two additional applications. You can also use a systemic insecticide like Orthene for control.
Q. How do you propagate crown-of-thorns? How big do they grow and do they have bad roots?
A. Propagate crown-of-thorns from branches 6 inches long. Let the branches dry for a day before sticking them in an unglazed pot with cactus soil mix. They propagate best between March and July. The big varieties grow to 4-5 feet in height. The dwarfs grow to 3 feet tall. Neither has invasive roots.
Q. Can you tell me where to obtain the big crown-of-thorns? All the nurseries only seem to sell the mini types.
A. Big varieties of crown-of-thorns have bigger leaves and can grow to at least 4-5 feet tall. `American Beauty' is one of the big varieties. My objection to these plants is that they have a tuft of leaves and flowers on top and lots of exposed thorny stems which does not exactly make them attractive. The dwarfs stay much tighter in growth without all the ugly exposed stems. I have seen the big variety at several nurseries; ask your local nursery to get them for you. As the plants grow they will eventually reach the 5-foot height range. They need full sun and minimal water.
Q. Our crown-of-thorns has gotten leggy and seems to have lost its color. Why?
A. Yours may be either planted too deep or be in a low spot in the bed where the water doesn't drain off quickly. Keep crown-of-thorns very dry. They can get root rot and fungal problems from too much water. Crown-of-thorns loves sun and if your plants are at the shady end of the bed that can also cause them to be off color and more leggy
Q. I have tried rooting hibiscus and have not been successful. How can I make it root?
A. You probably attempted rooting at the wrong time of the year. Cuttings can be rooted from June through August with good success.
Q. Can you tell me about wild coffee and where I can get this plant?
A. Wild coffee is an understory plant that grows in the hammock areas of south Florida. Its red berries are attractive and resemble the common coffee fruit. Wild coffee normally grows to 5 feet in height. Sources include Native plant nurseries and Native Plant Society sales.
Q. I miss my lilacs. Can I grow lilac bushes in south Florida?
A. Lilacs are not suited to south Florida. They cannot tolerate the prolonged heat and humidity of the summer. Lilacs also must have an extended cold season to thrive. They grow as far south as the mountains of South Carolina and Georgia. They are very cold tolerant and are hardy quite far north to Canada. Use great caution in ordering from mail order sources. We are located in Zone 10 and 11 on most hardiness maps. Most mail order nurseries serve wide areas of the country and have few things geared for this area. However, one reader said she had a lilac bush. She picked the leaves off the plant in early November to simulate winter and watered with ice water over the winter months. She let the plant leaf out again in March. I think her plant will eventually die. It seems like plant abuse to me. I would suggest visiting local botanical gardens to become familiar with the beautiful plants that you can grow down here. You can also invest in plant books at local nurseries or in the gift shops at these gardens to help you in selecting plants for the area. It is exciting when you think that the lilac blooms maybe two weeks up north whereas here you can have plants in bloom year round. Crape myrtle might be a good substitute for a lilac as the flowers are very similar, but not fragrant. They bloom from June to October and come in shades of white, pink, red, fuschia and purple.
Q. I saw a beautiful plant called mussaenda. Can you tell me where is the best place to plant it?
A. Mussenda is spectacular in the warm months with colorful bracts of pink or white. This large shrub goes bare over the winter and is very tropical so it should be placed where it has protection from winter winds. It takes sun to partial shade.
Q. You mentioned some time ago that tibouchina was a difficult plant for south Florida. Ours is doing well. We give it lots of water
A. Congratulations on growing a difficult plant successfully. My viewpoint is based on lots of observations over the years. These Brazilian plants like acid soil to do well. Most of our soil is alkaline so they are challenging at best. Fertilize with an acid fertilizer for ixoras and gardenias in March, June and October. Your tibouchina has large purple flowers and fuzzy leaves and is Tibouchina semidecandra or glory bush. The small tree form does better here and is called the purple glory tree, Tibouchina granulosa. Both types do better in interior areas of the counties with the heavier muck type soil.
Some web sites to visit:
The American Hibiscus Society at http://www.trop-hibiscus.com
Florida Plants Online at http://www.floridaplants.com