Extension Educator, Local Food Systems and Small Farms
Extension Educator, Horticulture
December 22, 2008
Houseplants do not thrive during the winter due to adverse growing conditions. However, houseplant pests such as mites, aphids and scales do.Plants are more likely affected by insect and related pest problems when under stress, states David Robson, University of Illinois Extension horticulture educator, Springfield Center. Fortunately, most insect-related damage is visible even though the pest might not be. Spider mites are not true insects, having eight legs instead of six. Damage from spider mites usually occurs when temperatures are cool and humidity levels are low. The first noticeable sign of mite-infected plants is a speckling of foliage. Leaves will be dotted with yellow spots that slowly turn brown. Careful observation of the underside of leaves might reveal tiny webs, especially between the leaf and stem. Mites can be seen with a sharp eye or a magnifying glass. They are usually reddish, move slowly and can be found underneath leaves and in growing shoots. Mites are most common on palms, scheffleras, crotons, cyclamen and cacti. Aphids, sometimes called plant lice, suck the sap from the leaves, stems and buds. Droplets of sticky sap may coat the plant parts. Most aphids are green, clear or white on houseplants. Like mites, the insects do not have wings and seldom migrate much from their original location. Aphid-damaged leaves appear twisted and distorted. New growth may be small and yellowish. Most flowering plants are bothered by aphids—especially hibiscus. Foliage plants such as palms also seem prone to aphid attacks. Scales are another one of the sap sucking insects that do not move. Brown armor-plated circles are usually found lined up on stems and occasionally leaves. Scales lay eggs beneath this shell. As soon as the young crawlers hatch, they move to another location and start secreting a shell for protection. Ferns are susceptible to scales as are woody-stemmed plants. However, scales seldom appear on the underside of fern fronds. What looks like scales may actually be fern spores, the sign of a healthy plant. Insect and related pest problems can be controlled with regular inspections. Infested plants should be isolated and treated. Insecticidal soaps provide the best control indoors for mites and aphids. Carry the plant to a sink before spraying. Always read and follow the labeled directions. A few aerosols are also available on the market for controlling aphids and mites. Make sure you keep the can at least 12 inches from the plant to avoid "freezing" the leaves with the super cold spray. Scales need more attention. Each should be carefully removed with a toothpick, Q-tip or dull knife. Dab each location with a cotton swab or Q-tip dipped in rubbing alcohol to kill any scale eggs or adult remaining. Wash the dabbed areas within five minutes to prevent the alcohol from drying the plant tissue. Check plants weekly after treating. Repeat applications of insecticidal soap or alcohol may be needed for three or four weeks. When bringing a new plant indoors, keep it isolated from the others for at least a month. Observe it weekly for signs of insects. It may be wiser to discard some severely infested plants instead of trying to cure them, adds Robson. The chance of insects spreading to other plants should always be kept in the back of your mind.
December 22, 2008
Green plants have become very popular in homes. Most gardeners have learned how to handle such plants indoors with little difficulty. These plants are pleasant additions to our homes, but many gardeners are looking for something different—a new challenge.
Flowering plants can provide an added dimension to our indoor gardens. If you can grow green plants, you can grow flowering plants too. However, you will have to learn not only how to grow the plants, but how to get them to flower. There is tremendous satisfaction in getting a plant to grow, develop and burst forth with a profusion of bloom.
African violets are without a doubt the most commonly grown flowering plant indoors. They require 10 hours of light and moderate temperatures, and they resent having wet leaves. Once they become accustomed to their new home, they usually bloom faithfully and nearly year round.
Bromeliads are all related to pineapples. They grow in a similar fashion with a whorl of spiny leaves and a brilliant flower that develops in the midst of the whorl. They need well-drained soil, filtered light and household temperatures. When the plant has flowered, the center of the whorl deteriorates, but the new "pups" grow from the base.
Amaryllis are plants with strange habits. The large 4" bulbs are planted singly in pots with just enough room around them for a little soil. If watered immediately after potting, a bulb sends up a strong stem and, in six weeks or so, several 6-inch flowers. They may be red, orange, white or pink.
As the flowers fade, the bulb sends up several strap-like leaves that persist for several months. Plants sending up leaves in spring can be set outdoors in a protected place for the summer.
Repot, and bring in before frost. Dry off so leaves die back, and keep in a cool dry place for a couple of months. Then resume watering, and the cycle will repeat. Some people time the red flowers for Christmas each year.
There are several flowering shrubs that bloom well indoors. Oleander and hibiscus need only a bright warm place and will flower profusely. However, oleander is considered poisonous and should be kept away from children. Gardenia grows well and sets flower buds easily; but if it is too hot or cold, too dark or light, too wet or dry, it will drop its buds before they open. Azaleas grow nicely indoors and can take a summer vacation outdoors. Flower buds develop during summer but need several weeks of cool temperatures (in the 40's) to break dormancy. Then when moved indoors, the buds break into bloom for a period of several weeks.
Most gardeners consider orchids the maximum challenge, yet there are some species that adapt well to home conditions. Cymbidiums, the smaller colorful corsage orchids are remarkably easy considering the reward for the effort. The plants grow from pseudobulbs in a light potting mix of at least half sand. A shoot of daylily-like leaves develops each spring.
In the late fall or early winter, one or two flower spikes develop from the base of a pseudo bulb. A spike may have a dozen or more flowers which last for weeks. Pick off one or two, and make a corsage if you like.
Cymbidiums like filtered light and cool temperatures indoors. In summer, they really enjoy a screened porch or sheltered spot outdoors. Do not be intimidated by their reputation—the orchids make delightful houseplants.
December 19, 2008
December 16, 2008
Cyclamen has become one of the favorite winter blooming pot plants. Newer, hardier varieties introduced during the 1980's have increased the ease with which it can be grown and has led to increased popularity, states David Robson, University of Illinois Extension horticulture educator, Springfield Center.
The flowering period of the cyclamen is from mid-November or early December until well into spring. So, the cyclamen can add color and cheer to a household during the long, dreary winter months.
Cyclamens have either white, red or pink flowers that grow on tall stems above heart-shaped, blue-green or dark green leaves. The foliage is attractively marked with veins and light green splotches. Thirty or more blossoms may appear on the plant before it declines.
Cyclamen love cool temperatures and bright (not direct) light. A daytime temperature of 60 to 65 F is recommended with a nighttime minimum of 50 F. An ideal location is an unshaded east window, fairly close-up to the glass.
Cyclamen need relatively high humidity to remain attractive. To help maintain humidity, fill a large plate or broad, shallow pan with water. Set the cyclamen on an inverted dish, just up out of the water. The evaporating water will do a great deal towards maintaining humid air around the foliage and flowers.
Check soil moisture regularly. This plant requires plenty of water and good drainage. Keep water out of the foliage crowns.
Handled in this way, a well-budded specimen often continues blooming for 2 to 3 months. Bud blasting and leaf yellowing result from a hot, dry atmosphere, lack of water or insufficient light.
Although the cyclamen is difficult to re-bloom, you will be proud if you can be successful in your attempt. To carry it over for another season, gradually withhold water after the flowers are gone. When the foliage has withered, remove the "bulb" from the soil, clean off all of the soil and debris and store it in dry peat moss or vermiculite in a plastic bag at 50 degrees F.
Replant in good potting soil in May or June, keeping the upper half of the tuber above the surface. When well started, grow the plant in a cool, bright, protected spot outside, with partial shade during the hottest part of the day and with the pot sunk in a bed of moist peat moss.Through the summer water adequately, and feed about twice a month with a complete liquid fertilizer. Bring indoors before cold weather, and provide full sun and the temperatures suggested above. Flowering should occur by midwinter. With luck, your plant can be acceptably re-bloomed over a period of a year. Growing cyclamen from seed is discouraged, even though this is the only method used by professional growers. Germination is slow and erratic, and 9 to 15 months are needed to produce full sized blooming plants, even under the best greenhouse conditions.
December 15, 2008
The All-America Selections have been announced for 2009. Just in time for ordering in the seed catalogs coming our way! Check out the selections, or view past selections, at the link below:
December 11, 2008
During the Holiday Season there is much interest in other plants to brighten up the home. This link has information on many of the traditional favorites, as well as some of the not-so-traditional.
December 1, 2008
The poinsettia is a plant that is native to Mexico, and has become the traditional potted plant at Christmas time. While many believe that the red, pink, or white color is the flower, it is actually called a bract. Bracts are colored leaves. The true flowers are there, but they aren't very showy.
Many of the improved varieties offered today last an amazingly long time. To keep them looking good and lasting, keep the room temperatures between 60-68 degrees (if possible) and with very high humidity. Temperatures over 75 are really hard on poinsettias, especially with low humidity. Try to place your poinsettia by a bright window just out of direct sunlight. Remove it from the window at night if there is a danger of chilling. Keep soil moisture at moderate and uniform levels, and never let the pot stand in water.
Reblooming poinsettias is a common goal, but bear in mind that this is one of the most difficult plants to succeed with. If you're a gambler, or a die-hard horticulturalist, here are the basic steps to improve your success.
After you are done displaying your poinsettia, gradually withhold water. The leaves should soon turn yellow and drop. Store the dried-off plant in a cool (meaning 50-60 degree), dry, dark, basement room until April or May. During this period, water lightly with just enough to keep the roots and stems from drying out too much.
When you bring the plant back up, prune stems to about six inches. Remove from the pot, take some old soil from the roots, then repot using a well-drained mixture. If there are several plants in the pot, separate and pot them individually. Use a pot that provides plenty of room. Water the plant well and place in a warm, sunny spot for renewed plant growth. You can put the plants outside when frost danger has passed, but be wary of direct sun in the hottest part of the day. You may have to repot the plant if it becomes rootbound. If you're into starting cuttings, you may have decent success by starting new plant from the shoots that appear on your old cut-back plant in the spring.
Keep the plant actively growing during the summer months by watering regularly and applying a complete liquid fertilizer every couple of weeks. As new shoots form, pinch them back so that two nodes (leaf pairs) remain on each. Stop pinching off shoots in August. Also, you may want to remove some of the weaker stems completely, allowing only a few of the stronger ones to develop. Control insects as they appear, and if plants become diseased they should be pitched.
Before cool weather in the fall, place the plant inside in a south window with full sun through the day. Watch the temperatures and moistures. Temperatures should be 60-65 during the day and 70-75 at night. Moisture should be moderate. Starting the last week of September, your plant should only be exposed to natural sunlight (this means no house lights after dark). Probably the best method is to put the plant in a closet overnight. Once the leaf color forms you can increase non-daylight light.
With these recommendations, and a little bit of luck, your poinsettia should be ready for the holiday season.