FAQ Horticulture Questions

Frequently Asked Questions About Growing Tropical Plants


Q.  We moved to Ft. Pierce six months ago and planted several hibiscus.  Although they have been fed with both Miracle Gro and Miracid and look healthy and are 'bushing out' they but have produced very few blossoms. What should we do?

A.  In the last few years, hibiscus in many areas have not flowered well. The plants seemed to be healthy but flowers seldom opened in spite of the fact that many had buds. Upon closer examination, it was discovered that in the aborting flower buds, there were small golden colored maggots. The maggots are the larvae of gall midges. With a bi-weekly spraying of a systemic insecticide (Orthene wettable powder or Cygon 2E for example) the problem seemed to be alleviated, and we started seeing more flowers. Check to see if there are flower buds forming at the ends of new growth. If  buds are present but they don't develop, try the insecticide approach. If no buds are forming the problem could be related to too much nitrogen fertilizer or insufficient light. 

Q.  We have a blooming bromeliad that has several "baby" plants sprouting from around the main plant. Is this okay or do they need to be removed? Is it correct to water the plant from the top (into the plant) or should the soil be watered?

A.  The bromeliad pups do not have to be removed from the parent unless you wish to make more plants. Most look attractive as a clump. As the parent ages and dies, remove each leaf as it turns yellow. The best way is to split each leaf down the middle and pull each half to the side. It will tear from the base much more easily. Because of their symmetrical growth habit and the way most Neoregelia species flatten out when blooming, they look best grown as individual plants. The general rule is to cut a bromeliad pup off when it is 1/3 the size of the parent, and pot it in an extremely well drained potting soil. The major purpose of the soil is to hold the plant upright, not to provide moisture. In nature most bromeliads grow high on tree branches. They capture rain in the rosette formed by the leaves and absorb water and nutrients through specialized cells concentrated inside this rosette. To duplicate this in cultivation most bromeliads are watered in the center of the rosette enough that some of the water runs down into the roots. The center should not stay dry for long periods. Because bromeliads are so efficient at using fertilizer, a liquid fertilizer is used very sparingly, usually less that 1/4 strength about once a month. To avoid growing long floppy foliage the most common way to fertilize is to mist the weak fertilizer solution onto the foliage and in the center cup. The roots are also able to absorb nutrients and some hobbyists use a time release fertilizer in or on the potting soil, always keeping in mind moderation.

Q.  My neighbor has quite a few mature Ficus benjamina trees and has recently added a ficus hedge. One of the trees has already caused noticeable damage to my driveway. Is there a way to manage the root system from my property? Aren't they prohibited in Florida? 

A.  Ficus benjamina is not on the exotic pest list (categories 1) or prohibited but is included in the list of species that have shown a potential to disrupt native plant communities (categories 2). You often see F. benjamina used as hedges in South Florida because it is very easy to propagate and grows fast in our area. If planted in a row, it produces a nice, dense hedge in a short period of time, making it an easy choice in landscaping in new construction. To remedy the damage to the driveway you will have to remove the driveway surface and cut the roots. On the market, you can find various durable root barrier products. 

Q.  I would like my traveler's palms to grow as individual trees. One of them, keeps suckering. Is there anyway to control it?   If "Palm Special" is the correct fertilizer how much do I apply since there is no trunk to measure?  Why is one plant twisting slightly?

A.  There are actually two ecotypes of traveler's tree, Ravenala madagascariensis - not really a palm. One type forms large clumps, the other never suckers. If you wish to retain a single trunk, the only way is to keep removing the suckers as they emerge. Unfortunately there doesn't seem any way around it. I know of no chemicals which inhibit such growth. A sharp machete, or even a sturdy spade should remove the suckers and make every effort to do it while the shoots are very young and it will no doubt be easier. Eventually the rate at which the suckers are produced, slows down. Palm fertilizer works well for these plants. The rates refer to the diameter of the trunk at chest height, usually a pound per inch of diameter. In your case a liberal fertilizing in March, June and September of  two pounds or even more should encourage good growth. Mulching with organic matter - wood chips or municipally supplied shredded and chipped mulch is very good. The plants also respond to regular irrigation especially during dry seasons. The twisting of the crown may indicate that the trunk will soon begin to show above ground.

Q.  I have a potted red sealing wax palm growing outdoors. No matter what I do, with fertilizer or water, the trunk does not remain red. The end of some of the leaves are brown and from the mother palm the leaves peel from one side of the frond and it is losing fronds. Would separating the pups from the main palm help? Is separating the same as with bromeliads, i.e. cutting from the root closest to the mother palm and replanting the pup?

A.  Only the bases and stalks of the leaves are red, the stem under those encircling leaf bases is green. A red sealing wax palm normally shows green stem toward the bottom where the old leaves have died and fallen off. The browning of the leaf tips may be due to the plant drying out. Provide ample water so the soil is always moist and remember to feed regularly. A 100% controlled release fertilizer is suggested for container palms. I don't recommend removing the pups since they can be difficult to grow and you can damage or weaken the mother plant by taking them off. 

Q.  One week ago I had two, eight foot areca palms planted. They have developed dark spots on the leaves (approx. 5 mm dia.)  that seem to penetrate all the way through the leaves, with necrosis of the tips of the leaves.  Is this a fungus or some other infestation?  Or is it from the shock of transplanting since I believe they were field grown?

A.  The recently transplanted palms, Dypsis lutescens,  seem to be having a fungus problem. This is common at times like this when the plant is in a weakened state from stress. Treatment for the fungus problem is not recommended unless it gets noticeably worse. Given proper care it should go away in time. Good care means, in particular, that the palms are watered regularly, wetting the entire rootball each time and never letting the soil dry out between waterings. You should also fertilize regularly (see the following question and answer).

Q.  Do I need to fertilize my landscape palms? What should I use and how often?

A.  While many survive without fertilizer, palms really do respond to regular maintenance feeding and it will show in their overall appearance and rate of growth. Fertilizing keeps them strong and boosts resistance to pest and disease problems. There are many inorganic and organic fertilizers to choose from but a balanced, complete granular fertilizer with an N:P:K ratio of 2:1:3 and 100% slow release N and K is widely recommended for South Florida landscape palms. Make sure it includes the complete complement of micronutrients. Several companies put out mixes with these specifications and call this 2:1:3 fertilizer "Palm Special". Broadcast fertilizer evenly under the canopy of the palm, avoiding placement next to the trunk or casting fertilizer down in piles, which will burn roots. Follow directions for the rate and be sure to adjust the rate according to plant size. The most important fertilizing of the year is the late spring application (at the onset of the rainy season). Autumn fertilizing helps keep palms healthy through the harsher "winter" months. I recommend fertilizing a minimum of four times a year, e.g. 5-8lbs/medium-large tree in March (where irrigated, onset of rainy season where not), June, August, October. 

Q.  Is it all right to prune unsightly leaves from my palms?

A.  It is best to limit pruning to leaves that are dead, diseased/ pest-injured, or frost damaged. The idea is to remove green growth as little as possible. Green leaves provide energy for the plant through photosynthesis and you want to leave green growth wherever possible. Cuts in the green, living tissue can also be an entry site for pests or disease. Cut dead leaves off as near to the stem as possible or pull off entirely if the leaf base comes away with the leaf stem and blade. Wait until they can be pulled off easily so that there is no risk of tearing green tissue where the leaf base is attached to the stem. Removal of flower and fruit stalks seems to cause little trouble for the palm. Certain palms such as Washingtonia naturally hold onto their old leaves and form an attractive and characteristic skirt of dead leaves below the crown if left alone.

Q.  Can you tell me how to grow trees from coconuts? I have a large beautiful tree in my front yard which drops a large amount of coconuts several times a year. I was told to start the coconut in water until it splits. I was also told to put it half way into soil and keep it moist.

A.  Coconut seeds can be germinated using any number of techniques. Mainly, you want to keep them warm and moist. One method that is good for a few seeds is to float each of them in a five gallon bucket of water in full sun. When the seed germinates with a short shoot growing downward, you can take it out and plant it in soil. For germinating a lot of seeds, some people push them down into mulch where the moisture and heat of the mulch pile helps them germinate. The mulch falls away easily when you are ready to pot the young seedlings in soil. Of course, you can simply place each nut into a pot of potting soil, place them in full sun and water regularly. Note: If your tree is a Maypan hybrid, your seedlings will be varied with a wide range of characteristics from the Malayan and Panama parent plants. The sizes and coloration will vary, as will their resistance to lethal yellowing disease.

Q.  We had a stand of three coconut palms which were planted three years ago and were healthy for the first two years. Now one has died and one is sick, while the third still looks healthy and is fruiting. The sick one has leaves dying at the top, bottom, and center of the tree and it no longer fruits. We thought it was bud rot, so we applied copper and Mancozeb, but the sick one is not looking any better. What do you suggest?

A.  Without inspecting the plants, I would consider lethal yellowing as a possibility. This is a disease of palms which has a distinctive sequence of symptoms in coconuts: the first and symptom to be seen in mature plants is premature dropping of the nuts (green ones will fall, sometimes old dried fruits do not), which show a brown staining, then leaves successively yellow and die from the bottom of the crown up. The entire crown can brown in two months. In coconuts, before this sequence there is often one "flag leaf" up in the crown which turns yellow and dies. 

Another possibility, (again, without seeing the plants), is cold damage. The browning would look dark and not dried, and would occur on outer or most exposed areas of the crown. 

The only recommendation in either case would be to "wait and see", since there is no treatment for lethal yellowing and you have already effectively dealt with any possible fungal problems that come with cold damage. 

Q.  Is it possible to grow bougainvillea from cuttings or by other methods? What is the best way?

A.  Bougainvilleas are usually propagated by cuttings, except by breeders who grow them from seed. You can also start them by layering them. Cuttings, six to eight inches long, can be made from semi-hardwood or hardwood stems, preferably as they are about to start growing but a little later is also usually fine. Insert the cuttings halfway into a peat moss-sand or peat moss-perlite mixture which is kept damp, not wet, and placed in a warm humid environment. When you see that there are strong roots and the buds have started to grow, pot up the plants individually in regular potting soil, and grow them as you are growing the mother plant. 

Q.  An unruly bougainvillea in a corner of my fenced back yard is about 15' tall and spreads 10-12' laterally. Most of the growth is at the periphery of the plant, high over the wooden fence and extending sloppily out into the yard. There is a "sphere" of about 6-8 feet of thick, naked vine underneath all the new growth. That is the area I would like the plant to occupy as a dense, beautiful plant about 6' tall and wide. To accomplish this it seems I would need to prune back to the ground and start from scratch. I'm very new to gardening and I don't know if I can prune so severely without hurting the plant. Books that address pruning bougainvillea suggest pruning strategies but don't address the type of radical remodeling I have in mind. Any advice?

A.  Bougainvillea can take some drastic pruning when necessary, but it is far better to prune regularly (at least annually). Provided the area that you want to have flowers is in full sun, it should be possible to train it into the area you prefer. You do not describe the plant flowers or habit but is seems that you may have a type of bougainvillea which probably does not lend itself to shearing which some species do. For now at least here are some steps to get it in place. It is generally best to wait until flowers have faded. Cut out all dead branches at their source. Cut back one half of the remaining strong branches to 1/3 their length. Cut the remaining branches to 2/3 their length. About mid summer do another, lighter pruning. Cut out errant branches at their source. Cutting the tips of the branches at this stage will encourage further branching and therefore greater potential for flowering. This technique is likely to be successful only in full sunlight. This will provide a place to start.

Q.  What is the secret to get "blooms" on container specimens of bougainvilleas? I live in Dallas, Texas.

A.  We do not grow bougainvilleas in containers at Fairchild because they do so well in the ground. Generally, these plants grow in sunny sites with well-drained soils. Although they may bloom year-round, the best flowering is usually on new growth in the dry winter and spring months. I suggest that you give your plant as much sun as possible and do not overwater.

Q.  I received a potted blooming anthurium plant with no care instructions. Please help.

A.  There are several anthuriums on the market sold as house plants. Most of these are the small red, pink or burgundy colored that are well accommodated in a 6" pot with names like "Lady Anne", "Lady Beth", or "Lady Jane'". They are quite happy in shady, warm and humid situations. They may be used as border plants in frost free locations or as potted plants. Water them well and then allow the soil to breathe by drying to the point of just damp. Once a week wash the dust from the leaves and fertilize with any fertilizer recommended for house plants. If you have received a larger type of anthurium (A. andreanum), it will need more of an epiphytic environment with lots of moisture and humidity, as well as lots of fresh air and no standing water. 

Q.  Heliconia bihai (Kamehameha) was growing well in my Miami backyard, until almost half the stalks were cut that had grown on to my patio. I would like to grow this plant without buying seeds since it takes years for it to flower. Can you explain how to divide a rhizome so that I can grow back my lovely heliconia garden.

A.  The fact that many of the invasive stalks were cut in half really is not of great consequence. Perhaps the plant should be lifted, divided and replanted where it will not interfere with the patio. Heliconias are heavy feeders and tend to exhaust the soil in which they grow. You may notice that the center of the plant eventually seems to die out.  I usually dig up the plants with the bare centers, divide the plant into manageable pieces refurbish the soil (Put in new soil, add organic mulch and slow release fertilizer) and replant a division of the heliconia. The remaining pieces are discarded or given to friends or planted in other areas. The best time for this activity is during the warm weather times of the year. (Spring through early autumn). 

Q.  Can I grow heliconias indoors?

A.  Maybe... if you can provide enough light, humidity and warmth. While many people successfully grow heliconias in greenhouses, we generally don't recommend them as houseplants. The most common problems in keeping them healthy and flowering indoors are (a) controlling spider mites and (b) providing enough heat and humidity, especially at night .  Heliconias seem not to thrive if night temperatures are below 60°.