Master Gardener Update

Transcription

1 APRIL 2001 Master Gardener Update April Meeting The April 3, 7:00 PM meeting will be in room 154 University Park Building. Grant Mattheke is going to tell us about his trip to China to collect seeds. We will also be having birthday celebrations. Alaska Master Gardener Conference Will be in Palmer this year. April is the scheduled date. See page 6 for additional information. Land Resources Agent Michele Hébert Editor Jennifer Miller Design and Layout Inside... Pruning Large, overgrown Lilacs... 2 Pruning Continued... 3 Growing African Violets... 4 AK Master Gardener Conf...6 Memories of a spring past in the demonstration garden. Recognize anyone? This years class starts March 20, Prez Sez by Nina Megyesi, MG President...Where are those nominations for TVMG Association officers for 2001? So far we have a full slate but do not want to miss any volunteers. Our annual general meeting will be held April 3rd. That night we will have our elections and discuss any other business. As a reward for all members who attend the meeting we have a treat. Grant Matheke is going to tell us about his trip to China to collect seeds. He says to bring pillows as he has so much to say that we might fall asleep! Please study the calendar and be sure to remember to reserve the three work dates so you can help out at the Georgeson Botanical Garden. Calendar of Events Master Gardener Conference Palmer April Community Tree Stewards Classes April 25 -May 24 Plant sale at the Georgeson Botanical Garden GBG May 12 Clean up at the GBG May 19 Hospice plant sale May 26 International Master Gardener Conference May 27-June 2 Soil and water conservation district tree sale June 2-3 Fairbanks Garden Club Plant Sale June 2 Planting at the demonstration garden June 9 Planting at the GBG June 5 No endorsement of firms and products mentioned is intended, nor is criticism implied of those not mentioned in the Master Gardener Update.

2 Master Gardeners Update, April 2001 Pruning Large, Overgrown Lilacs Page 2 The common purple lilac is a tough, reliable shrub that may reach a height of 15 to 20 feet. Unfortunately, as lilacs mature, the shaded lower portions of the shrubs usually lose their leaves. As a result, large, overgrown specimens are often leggy and unattractive. Old, neglected lilacs can be renewed or rejuvenated by pruning. Home gardeners can choose between two different pruning methods. One way to renew a large, overgrown lilac is to cut the entire plant back to within 6 to 8 inches of the ground in late winter (April to mid May). This severe pruning will induce a large number of shoots to develop during the growing season. In late winter of the following year, select and retain several strong, healthy shoots to form the shrub framework and remove all the others at ground level. Head (cut) back the retained shoots to just above a bud to encourage branching. A second way to prune old lilacs is to cut back the overgrown shrubs over a three-year period. Begin the procedure by removing one-third of the large, old stems at ground level in late winter. The following year (again in late winter), prune out one-half of the remaining old stems. Also, thin out some of the new growth. Retain several well-spaced, vigorous stems and remove all the others. Finally, remove all of the remaining old wood in late winter of the third year. Additional thinning of the new shoots should also be done. Since lilac wood needs to be 3 or more years of age before it blooms, this pruning method should allow you to enjoy flowers every spring. When properly pruned, an old, overgrown lilac can be transformed into a vigorous attractive shrub within a few years. Once rejuvenated, pruning should be a regular part of the maintenance program for lilacs. The shrub can be kept healthy and vigorous by removing a few of the oldest branches every 3-5 years. The Proper Time to Prune An important aspect of pruning is knowing when to prune plants. Proper timing helps to insure attractive, healthy, productive plants. The proper time to prune various woody plants in the yard and garden are indicated below. Deciduous Shrubs Many deciduous shrubs are planted in the home landscape for their attractive flowers. Spring-flowering shrubs bloom in the spring on the growth of the previous season. Two widely planted examples are the lilac and forsythia. The proper time to prune spring-flowering shrubs is largely determined by their condition and the amount of pruning required. Old, neglected spring-flowering shrubs often require extensive pruning to rejuvenate or renew the plants. The best time to rejuvenate large, overgrown shrubs is late winter or early spring (mid-april to early May) before the plants begin to leaf out. While heavy pruning in late winter or early spring will reduce or eliminate the flower display for a few years, the restoration of a healthy, vigorous shrub is more important. If spring-flowering shrubs need only light pruning, prune them immediately after blooming. Pruning immediately after bloom allows the gardener to enjoy the spring flower display and gives the shrubs adequate time to initiate new flower buds for next season. Summer-flowering shrubs, such as potentilla and Japanese spirea, bloom in summer on the current year's growth. Prune these shrubs in late winter or early spring. Summer-flowering shrubs pruned early April will still bloom in summer. Many deciduous shrubs don't produce attractive flowers. These shrubs may possess attractive bark, fruit, or fall leaf color. Prune these shrubs in late winter or early spring. Don't prune deciduous shrubs in late summer. Pruning shrubs in August or early September may encourage a late flush of growth. This new growth may not harden sufficiently before the arrival of cold weather and be susceptible to winter injury. Continued pg 3 The University of Alaska Fairbanks Cooperative Extension Service programs are available to all, without regard to race, color, age, sex, creed, national origin, or handicap and in accordance with all applicable federal laws. Provided in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Anthony Nakazawa, Director, Cooperative Extension Service, University of Alaska Fairbanks.

3 Master Gardener Update, April 2001 Page 3 Evergreen Shrubs Prune evergreen shrubs, such as juniper and yew, in late April or early May before new growth begins. Light pruning may also be done in late June or early July. Avoid pruning evergreen shrubs in the fall. Fall pruned evergreens are more susceptible to winter injury. Deciduous Trees The best time to prune deciduous trees is late winter or early spring ( April to early Mayl) before they begin to leaf out. Some trees, such as maples, "bleed" heavily when pruned in late winter or early spring. However, the heavy bleeding doesn't harm the trees. The trees won't bleed to death and the flow of sap gradually slow and stop. If possible, avoid pruning deciduous trees in the spring as they are leafing out. At this time, the tree's energy reserves are low and the bark "slips" or tears easily. Another poor time to prune is during leaf drop in the fall. Evergreen Trees An excellent time to prune spruce is late winter when they are still dormant. Spruce possess side or lateral buds. The pruning cut should be just above a side bud or branch. Pines are pruned in early June to early July when the new growth is in the "candle" stage. Pinching or snapping off one-half to two-thirds of the candle reduces the pine's annual growth. Unwanted lower branches on all evergreen trees can be removed in late winter. Fruit Trees The best time to prune fruit trees is early April. Fruit trees pruned in fall or early winter may be susceptible to winter injury. Roses The upper portions of roses, winterkill due to exposure to low winter temperatures and extreme temperature changes. Gardeners should prune out the dead wood after the winter protection is removed from roses in late April to early May. Old garden roses, hybrid rugosas, and other hardy roses often survive winters with little or no winter injury. Those that bloom only once a year should be pruned immediately after flowering. Those that bloom throughout the summer should be pruned in April and late May.

4 Master Gardener Update April 2001 Growing African Violets Page 4 African violets are one of America's most popular houseplants. Under the right growing conditions, they are able to bloom almost continuously indoors. They are also available in a wide range of flower colors, leaf types, and growth habits (trailing, miniature, standard, etc.). History The history of African Violets dates back to the late 18th century. Baron Walter von St. Paul discovered these blooming beauties growing in West Africa and sent samples or seed home to Germany. By the early 1900's African violets were blooming in Europe and around the world. The development of hybrid varieties with violet, purple, and blue flower colors in the late 1920's by the Los Angeles nursery of Armacost and Roysten increased the popularity of African violets. Since the 1920's hundreds of cultivars have been developed with an immense variety of flower and leaf colors, shapes, and sizes. Colors, Types, and Habits Today, flower colors include blue, purple, red-violet, orchid, lavender, red pink, white, and bicolor or multicolored. There are single, double, semi-double, star-shaped, fringed, and ruffled flower types. Leaf types include plain, ruffled, fringed, scalloped, spooned, pointed, and variegated. The American Violet Society has 4 classes of African violets based on plant size: miniature (less than 6 inches in diameter), semi-miniature (6 to 8 inches), standard (8 to 16 inches), and large (over 16 inches). No matter which flower color, leaf type, or habit you select, the care for all types of African violets is similar. While these are relatively easy to grow houseplants, they do require consistent care. Light Proper light is essential for good bloom. African violets require more light than most growers first realize. Thin, dark, blue-green leaves with long petioles indicate insufficient light levels. While moderate light is needed, direct light for long periods can be damaging as well. Too much light produces leaves that are small, crinkled, leathery, and yellow with short petioles on stunted plants. Generally, north and eastern exposures are best for African violets. However, if these exposures are not possible, African violets perform beautifully under artificial lights as well. Fluorescent lights suspended approximately 8 inches above the plants for 12 to 16 hours per day will produce sufficient light to initiate blooms in African violets. Temperature African violets require temperatures between 65 and 80F. Typically, temperatures below 50 F will cause leaves to darken, become water-soaked, and wither. Temperatures above 85F will slow growth and flowering of African violets and may injure the leaves as well. Water temperature becomes important during the winter months, as cold water directly on the leaves will damage them quickly. Watering Watering African violets is often the most difficult part of their care. They require a moist, well-drained soil. If the soils are too wet, the plants may rot. If plants are too dry, they will not grow or flower well. Many people sub-irrigate African violets. This means placing the plant in a saucer of water and allowing the plant to soak up water from the bottom of the pot. This prevents injury from cold water on the leaves and insures the entire soil profile is moist. However, care must be taken not to allow the plants to sit for long periods in water as they may rot quickly. Allow the top inch of the soil to dry before accumulation of salts. Continued pg 5

5 Master Gardener Update April 2001 Page 5 subirrigating again. African violets can also be watered from the top if room temperature water is used and the foliage remains dry. In fact, it is recommended to irrigate from the top occasionally to prevent salt accumulation. Wick watering is another method that is increasing in popularity. This is a continuous watering system with a water reservoir at the base of the plant and an absorbent wick that connects the soil and the water reservoir. This method is effective in maintaining an even moisture level of the soil. However, periodic leaching of the soil profile with water from the top might be necessary to prevent the Fertilization Regular fertilization is needed to encourage plants to bloom throughout the year. A complete fertilizer at a low rate is recommended. Excessive fertilization leads to vigorous vegetative growth, poor flowering, and the accumulation of salts in the soil. The accumulation of salts can ultimately damage or destroy foliage. Flush soils occasionally with clear water to eliminate salt buildup in the soil. Soils A loose, porous, fertile soil or soilless mix that is slightly acidic (6.0 or 6.5) is needed for growing African violets. Peat-based soils that have been pasteurized are best. Garden or field soil is not satisfactory alone since it is often poorly drained and compacts easily. Many commercial soilless mixes are available. African violets make great houseplants. With a proper environment and regular care they will reward you with blooms all year. Insects and Disease If grown properly, African violets have few problems with insects or diseases. Some of the more common pest problems include mites and mealybugs. Mites are small spiders that attack the undersides of the leaves, new growth, and flowers. Small webs are normally found around the leaf axils (junction of leaf petiole and main stem). Mites are so small they are not visible to the naked eye and the damage to the plant is often noticed first. Control of mites may require isolating the infected plant and spraying with soapy water or a miticide. Mealybugs are easier to identify, as they are larger than spider mites. Mealybugs are whitish and often exude a "cottony mass" of sticky material for protection. Control requires soapy water baths or removal of the bugs with alcohol dipped cotton swabs. Whenever, the foliage of African violets are wetted, warm water must be used and sufficient time allowed for the leaves to dry out before dark. Foliage that stays moist is prone to fungal diseases. One common fungal foliar disease is powdery mildew. Infected leaves will have small circles of a gray or whitish powder on the topside of the leaves. Control for powdery mildew requires the removal of infected leaves and spacing plants out more for better air circulation between plants. Powdery mildew tends to more of a problem on plants that are overcrowded. Crown rot is another common fungal problem of African violets that are overwatered. Crown rot causes the main stem and lower leaves to appear water-soaked, shrivel and die. Crown rot usually leads to death of the plant. Allowing the top of the soil to dry out between watering will prevent crown rot.

6 Master Gardener Newsletter April 2001 Page 6 Thursday -Saturday April Celebration of Spring Alaska Master Gardener Conference Mark your calendar now for the 2001 Garden Conference and Garden Fair coming to Raven Hall at the Alaska State Fairgrounds. Enjoy 2-1/2 days of gardening tours, seminars, and workshops. A schedule of events, reservation information and lots more details will be arriving in your mail. Tell your friends and family - don't miss the biggest gardening event of the year! Mat-Su Master Gardeners Conference Registration c/o Dorte Mobley 575 Jerome Drive Wasilla, AK Phone: danishdream@matnet.com Alaska Garden Conference and Garden Fair presented by Mat-Su Master Gardeners Association COOPERATIVE EXTENSION SERVICE U.S. DEPARTMENT OF AGRICULTURE UNIVERSITY OF ALASKA FAIRBANKS PO BOX FAIRBANKS AK PRSRT STD POSTAGE & FEES PAID USDA PERMIT No. G268 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, $300