Hort Update for the week of 2/1/2010
Bolded items are new in this issue of Hort Update
1. Snow and ice effect on turfgrass. Snow is a good insulator for turf protecting it from winter drying and extreme cold temperatures. If a frozen layer of ice develops beneath snow, turfgrass may be smothered due to oxygen exchange problems. Turfgrass will withstand 90 days of snow cover, but only 60 to 70 days of ice cover. Long periods of compacted snow also increase the incidence of gray snow mold. Avoid walking on snow covered turfgrass to prevent compacting snow and development of an ice layer. Wait and see what the effects are this spring; repair with overseeding and good turf management practices if needed.
Effects of Extreme Weather on Landscapes Remains to be Seen, eXtension.org
2. Deer pawing to reach grass below snow have caused damage to some turf in eastern Nebraska. Repair damaged areas with overseeding this spring. Think twice about feeding wildlife as this can attract and increase wildlife populations in an area; eventually leading to an increase in damage.
3. Ice melting products can harm soil structure, plants, concrete and carpeting. Five chemicals are commonly used as deicing agents. Choose and use wisely for safety and for the environment. Calcium magnesium acetate (CMA) is a salt-free melting agent made from dolomitic limestone and acetic acid. Studies have shown CMA has little impact on plants and animals. Sodium chloride or rock salt has little or no effect on concrete, but can damage soil structure, burn plants and corrode metal. Calcium chloride in weak solutions generally has little effect on concrete and soil, but does corrode metal. In concentrated solutions, it can damage plants, concrete, skin, and stain carpets and shoe leather. Urea won’t chemically damage concrete, vegetation or metal, but has limited effectiveness in melting ice. If used as a deicer, lawns adjacent to pavement may grow excessively in spring which can lead to summer disease problems. Potassium chloride has a high salt index and does have potential to burn foliage and inhibit rooting.
Winter Deicing Agents for the Homeowner, University of Nebraska- Lincoln Extension
4. Snow/ice build-up on plants leads to limb breakage. It can also result in less obvious splits and cracks in trunks and limbs which pose a risk long after the storm. As a general rule, let snow and ice melt naturally from tree limbs. If it is safe to do so, gently remove snow from limbs. Hold onto the limb from below and gently brush off loose snow. Watch for falling limbs and ice from above. Do not hit a branch to knock off snow or ice. Always let ice melt naturally. Do not try to dig snow away from shrubs as this leads to damaged limbs.
Effects of Extreme Weather on Landscapes Remains to be Seen, eXtension.org
6. Wildlife damage to woody plants increases with snow covering most food sources as well as exclusion methods put into place during fall. If exclusion methods, i.e. hardware cloth, can feasibly be put into place or extended above the snow line, this is the best protection against wildlife. Various taste repellents, such as Thiram or Millers Hot Sauce, can be effective in reducing deer and rabbit damage as long as animals have other food sources to turn to. Scent repellents, such as bags of human hair or bar soaps on a rope, have been shown to be effective in some situations. Repellents wear or wash off and repeat applications are needed. Think twice about feeding wildlife as this can attract and increase wildlife populations in an area; eventually leading to an increase in damage.
Deer Damage Management, eXtension.org
Rabbit Damage Management, eXtension.org
7. ReTree Nebraska, a Nebraska Forest Service program, has identified ten trees for planting in Nebraska to improve the quality and diversity of our states community forests. These trees are Concolor fir, Black Hills’s Spruce, Shantung maple, Miyabe maple, Kentucky coffeetree, Northern Catalpa, Bald Cypress, Bur Oak, Chinkapin oak, and Elm Hybrids. Learn more about the characteristics of these trees out. If one or more are adapted to the growing conditions of your planting sites, select one for planting.
ReTree Nebraska’s Ten for 2010
8. GreatPlants® for the Great Plains, a program of the Nebraska Statewide Arboretum and the Nebraska Nursery and Landscape Association, has identified the 2010 GreatPlants. They are American Yellowwood, Swiss Stone Pine, Bottlebrush Buckeye, ‘Gateway’ Eupatorium and Sand Lovegrass. Consider planting one or more of these plants if they are adapted to the growing conditions of your planting site.
2010 GreatPlants® Selections, Nebraska Statewide Arboretum
9. Fruit Tree Pruning is best done when trees are dormant. During March, when temperatures may be less extreme, is the best time to prune fruit trees. A small amount of annual pruning encourages production of fruiting wood and opens trees to increased light penetration which increases fruit production and quality. When pruning fruit trees, understand what age wood the different species bear fruit on. Make proper pruning cuts and use sharp pruning tools. Do not use pruning paints or wound dressings on pruning wounds. If a fruit tree sustained storm damage, consider removing the tree if over 50% of the trees branches need to be removed due to breakage.
Pruning Fruit Trees, Kansas State University Extension
10. Starting seeds indoors for transplants allows gardeners to grow varieties that are not available to buy locally. Growing quality transplants requires the right growing conditions and not starting too early. Depending on the vegetable, start most transplants about 6 weeks prior to the expected outdoor planting date. To grow quality transplants, use a soilless potting mix and provide fairly high humidity, cool temperatures (60 to 70 degrees F.) and 14 to 16 hours of bright light per day. Use a grow light or one cool white and one warm white fluorescent light, placed one to two inches from the plants. A little air movement, such as with a fan, can also lead to sturdier transplants.
Growing Transplants, University of Illinois Extension
11. Checking seed viability: Test the germination rate of leftover seed before buying new. The seeds of many plants can remain viable for up to 5 years if stored correctly. Conduct a germination test by placing some seed between paper towels that are kept constantly moist and at a temperature between 65 and 70 degrees F. Check seeds daily for sprouting. If, after 7 to 10 days, the germination rate is seventy percent or less, consider buying new seed.
12. Aphids are small, usually green, soft-bodied insects found crowded together on the undersides of new leaves. If a houseplant or the surface a houseplant is setting on feels sticky, the plant may be infested with aphids which excrete a sticky honeydew while feeding on plant sap. Use a combination of control measures, such as syringing (washing) followed by the use of a labeled product. Products labeled for use on houseplants include insecticidal soaps, horticultural oils, Neem oil, synthetic insecticides such as those containing pyrethrins and systemic insecticides applied to the soil for plant uptake. Read and follow label directions for safe and effective control and repeat treatment as recommended. Most houseplant pests will not be controlled with one syringing or one product treatment. Monitor houseplants closely for insects or signs and symptoms of insects.
13. Spider mites cause leaves to appear speckled, then bronzed or brown in appearance. Leaf yellowing and a dirty appearance to plants are other signs of spider mites. Spider mite populations multiply rapidly due to warm, dry indoor air and no predators to eat them. Control spiders mites using the same methods recommended for aphids.
14. Low humidity levels in homes lead to browning of leaf tips and leaf edges of many houseplants, which are natives of the tropics and adapted to high humidity levels. Humidity may be increased by placing plants on trays filled with pebbles and water to within one half inch of the base of the pot.
15. Fungus gnats are small fly-like insects that may be noticed flying around houseplants. They are commonly associated with overwatered houseplants or those grown in poorly drained potting mixes. If a houseplant pot is harboring fungus gnats, treat the soil with insecticidal soap or incorporate diatomaceous earth in the soil to kill the maggots. Another approach is to cut back on watering so soil dries out between watering. Any maggots present in the soil will dry out, and lack of water will reduce fungal growth, reducing the food supply for adult fungus gnats. A third option is a combination of letting the soil dry between watering and then watering with a solution of water and insecticidal soap.
Fungus Gnats
Bolded items are new in this issue of Hort Update
| Lawns | Major Symptom: |
| 1. Snow/Ice effects on turfgrass | Ice layer worse than snow. Avoid walking on snow over grass. |
| 2. Deer damage to sod | Deer may damage sod while pawing through snow to feed. |
| 3. Ice melting products | Choose wisely. Products can damage soil, plants, concrete, carpet. |
| Trees & Shrubs | |
| 4. Snow/ice build-up on plants | Let snow and ice melt naturally. Repair damage when it’s safe. |
| 5. Winter pruning | Winter is a good time to prune shade trees. Use caution. |
| 6. Wildlife damage | Use exclusion methods or repellents. Careful of feeding wildlife. |
| 7. Trees for 2010 | ReTree Nebraska recommends 10 trees planting in Nebraska. |
| Landscape Ornamentals | |
| 8. GreatPlants® for the Great Plains | Four great plant selections for Nebraska landscapes. |
| Fruits & Vegetables | |
| 9. Pruning fruit trees | Prune while dormant, but avoid too early pruning. |
| 10. Starting seeds/ transplants | Provide right growing conditions; don’t start seeds too early. |
| 11. Checking seed viability | Conduct germination tests to determine viability of older seed. |
| Indoor Plants | |
| 12. Aphids | Sticky feeling or shiny appearing leaves; leaf yellowing |
| 13. Spider mites | Stippled leaves with bronze to brown discoloration |
| 14. Low humidity | Brown leaf tips and leaf edges |
| 15. Fungus gnats | Small fly-like insects flying around houseplants |
1. Snow and ice effect on turfgrass. Snow is a good insulator for turf protecting it from winter drying and extreme cold temperatures. If a frozen layer of ice develops beneath snow, turfgrass may be smothered due to oxygen exchange problems. Turfgrass will withstand 90 days of snow cover, but only 60 to 70 days of ice cover. Long periods of compacted snow also increase the incidence of gray snow mold. Avoid walking on snow covered turfgrass to prevent compacting snow and development of an ice layer. Wait and see what the effects are this spring; repair with overseeding and good turf management practices if needed.
Effects of Extreme Weather on Landscapes Remains to be Seen, eXtension.org
2. Deer pawing to reach grass below snow have caused damage to some turf in eastern Nebraska. Repair damaged areas with overseeding this spring. Think twice about feeding wildlife as this can attract and increase wildlife populations in an area; eventually leading to an increase in damage.
3. Ice melting products can harm soil structure, plants, concrete and carpeting. Five chemicals are commonly used as deicing agents. Choose and use wisely for safety and for the environment. Calcium magnesium acetate (CMA) is a salt-free melting agent made from dolomitic limestone and acetic acid. Studies have shown CMA has little impact on plants and animals. Sodium chloride or rock salt has little or no effect on concrete, but can damage soil structure, burn plants and corrode metal. Calcium chloride in weak solutions generally has little effect on concrete and soil, but does corrode metal. In concentrated solutions, it can damage plants, concrete, skin, and stain carpets and shoe leather. Urea won’t chemically damage concrete, vegetation or metal, but has limited effectiveness in melting ice. If used as a deicer, lawns adjacent to pavement may grow excessively in spring which can lead to summer disease problems. Potassium chloride has a high salt index and does have potential to burn foliage and inhibit rooting.
Winter Deicing Agents for the Homeowner, University of Nebraska- Lincoln Extension
4. Snow/ice build-up on plants leads to limb breakage. It can also result in less obvious splits and cracks in trunks and limbs which pose a risk long after the storm. As a general rule, let snow and ice melt naturally from tree limbs. If it is safe to do so, gently remove snow from limbs. Hold onto the limb from below and gently brush off loose snow. Watch for falling limbs and ice from above. Do not hit a branch to knock off snow or ice. Always let ice melt naturally. Do not try to dig snow away from shrubs as this leads to damaged limbs.
Effects of Extreme Weather on Landscapes Remains to be Seen, eXtension.org
5. Winter is one of the best times to prune shade trees. With snow and ice causing limb breakage, pruning to remove and repair broken limbs is needed. Wait for ice and snow to melt before pruning damaged trees. Use caution when pruning trees this year. Snow and ice loads may have caused splits and cracks in limbs that are not obvious. Refer people to Certified Arborists when dealing with larger, storm damaged trees. If more than 50 percent of a tree’s branches need to be removed due to storm damage, consider removing the tree. Otherwise, use good pruning practices.
- Never leave stubs.
- Cut damaged branches back to laterals or to the trunk but preserve branch collars by making cuts just outside of the collar and branch bark ridge.
- Use the three-cut method for larger branches to prevent bark stripping.
6. Wildlife damage to woody plants increases with snow covering most food sources as well as exclusion methods put into place during fall. If exclusion methods, i.e. hardware cloth, can feasibly be put into place or extended above the snow line, this is the best protection against wildlife. Various taste repellents, such as Thiram or Millers Hot Sauce, can be effective in reducing deer and rabbit damage as long as animals have other food sources to turn to. Scent repellents, such as bags of human hair or bar soaps on a rope, have been shown to be effective in some situations. Repellents wear or wash off and repeat applications are needed. Think twice about feeding wildlife as this can attract and increase wildlife populations in an area; eventually leading to an increase in damage.
Deer Damage Management, eXtension.org
Rabbit Damage Management, eXtension.org
7. ReTree Nebraska, a Nebraska Forest Service program, has identified ten trees for planting in Nebraska to improve the quality and diversity of our states community forests. These trees are Concolor fir, Black Hills’s Spruce, Shantung maple, Miyabe maple, Kentucky coffeetree, Northern Catalpa, Bald Cypress, Bur Oak, Chinkapin oak, and Elm Hybrids. Learn more about the characteristics of these trees out. If one or more are adapted to the growing conditions of your planting sites, select one for planting.
ReTree Nebraska’s Ten for 2010
8. GreatPlants® for the Great Plains, a program of the Nebraska Statewide Arboretum and the Nebraska Nursery and Landscape Association, has identified the 2010 GreatPlants. They are American Yellowwood, Swiss Stone Pine, Bottlebrush Buckeye, ‘Gateway’ Eupatorium and Sand Lovegrass. Consider planting one or more of these plants if they are adapted to the growing conditions of your planting site.
2010 GreatPlants® Selections, Nebraska Statewide Arboretum
9. Fruit Tree Pruning is best done when trees are dormant. During March, when temperatures may be less extreme, is the best time to prune fruit trees. A small amount of annual pruning encourages production of fruiting wood and opens trees to increased light penetration which increases fruit production and quality. When pruning fruit trees, understand what age wood the different species bear fruit on. Make proper pruning cuts and use sharp pruning tools. Do not use pruning paints or wound dressings on pruning wounds. If a fruit tree sustained storm damage, consider removing the tree if over 50% of the trees branches need to be removed due to breakage.
Pruning Fruit Trees, Kansas State University Extension
10. Starting seeds indoors for transplants allows gardeners to grow varieties that are not available to buy locally. Growing quality transplants requires the right growing conditions and not starting too early. Depending on the vegetable, start most transplants about 6 weeks prior to the expected outdoor planting date. To grow quality transplants, use a soilless potting mix and provide fairly high humidity, cool temperatures (60 to 70 degrees F.) and 14 to 16 hours of bright light per day. Use a grow light or one cool white and one warm white fluorescent light, placed one to two inches from the plants. A little air movement, such as with a fan, can also lead to sturdier transplants.
Growing Transplants, University of Illinois Extension
11. Checking seed viability: Test the germination rate of leftover seed before buying new. The seeds of many plants can remain viable for up to 5 years if stored correctly. Conduct a germination test by placing some seed between paper towels that are kept constantly moist and at a temperature between 65 and 70 degrees F. Check seeds daily for sprouting. If, after 7 to 10 days, the germination rate is seventy percent or less, consider buying new seed.
12. Aphids are small, usually green, soft-bodied insects found crowded together on the undersides of new leaves. If a houseplant or the surface a houseplant is setting on feels sticky, the plant may be infested with aphids which excrete a sticky honeydew while feeding on plant sap. Use a combination of control measures, such as syringing (washing) followed by the use of a labeled product. Products labeled for use on houseplants include insecticidal soaps, horticultural oils, Neem oil, synthetic insecticides such as those containing pyrethrins and systemic insecticides applied to the soil for plant uptake. Read and follow label directions for safe and effective control and repeat treatment as recommended. Most houseplant pests will not be controlled with one syringing or one product treatment. Monitor houseplants closely for insects or signs and symptoms of insects.
13. Spider mites cause leaves to appear speckled, then bronzed or brown in appearance. Leaf yellowing and a dirty appearance to plants are other signs of spider mites. Spider mite populations multiply rapidly due to warm, dry indoor air and no predators to eat them. Control spiders mites using the same methods recommended for aphids.
14. Low humidity levels in homes lead to browning of leaf tips and leaf edges of many houseplants, which are natives of the tropics and adapted to high humidity levels. Humidity may be increased by placing plants on trays filled with pebbles and water to within one half inch of the base of the pot.
15. Fungus gnats are small fly-like insects that may be noticed flying around houseplants. They are commonly associated with overwatered houseplants or those grown in poorly drained potting mixes. If a houseplant pot is harboring fungus gnats, treat the soil with insecticidal soap or incorporate diatomaceous earth in the soil to kill the maggots. Another approach is to cut back on watering so soil dries out between watering. Any maggots present in the soil will dry out, and lack of water will reduce fungal growth, reducing the food supply for adult fungus gnats. A third option is a combination of letting the soil dry between watering and then watering with a solution of water and insecticidal soap.
Fungus Gnats
