Garden Talk

with Rebecca Jordi


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Choosing wind resistant trees

dsc04994editNow that Hurricane Matthew is gone and some of our trees came down there is often a “knee jerk” reaction to take all the trees down from around the house.  Perhaps we need to take some time and rethink this position because trees provide so much to us and the environment. If trees need to be replaced then let’s consider planting some tree with high to moderate wind resistance.

 

But, before I give you a list of trees to replant I want to mention we can make a good selection but do the wrong things to trees and alter their ability to withstand high winds.  Over-pruning trees or using improper pruning techniques will directly alter the trees ability to withstand storms.  Do not cut the top off the tree, no lion’s tail cut which generally removes the interior foliage.  No over-pruning to “raise the canopy.”   Be sure to call a certified arborist to prune trees.  Planting trees too deeply will show limb dieback on the tree very early.  Over-mulching – NO mulch volcanoes, mulch should only be 2-3 inches deep and never be close to the trunk of any tree of large shrub.  Over-watering – we should not water trees and shrubs the same way we water grass.  After a few years the trees and shrubs do not need irrigation unless we do through a drought period.  Growing grass up to the trunk of the tree – grass and trees are terrible partners.  The things we do to grass we should never do to trees.  Leave as large an area as possible with no grass.  Planting large shrubs around the base of the tree is a poor practice.  Adding soil to the roots of the tree – even a few inches can cause a loss of air around the roots.

 

This following information was taken from research done by the University of Florida in 2005 titled, “Selecting Tropical and Subtropical tree species for wind resistance.”

 

  1. One of the most important findings is the rooting space: the more rooting space that a tree has, the healthier it is, meaning better anchorage and resistance to wind.
  2. Trees growing in groups or clusters were also more wind resistant compared to individual trees. This might be an especially good strategy for tree establishment in parks or larger yards. Especially significant for those green belted areas.
  3. Proper should be considered an important practice for tree health and wind resistance

 

This list is not all of the trees but it will give you a good place to start:

Highest wind resistance for North Florida:

Carya floridana, Florida scrub hickory; Conocarpus erectus, buttonwood; Ilex cassine, dahoon holly;

Lagerstroemia indica, crape myrtle; Magnolia grandiflora, southern magnolia; Podocarpus spp, podocarpus; Quercus virginiana, live oak; Quercus geminata, sand live oak; Taxodium ascendens, pondcypress;

Taxodium distichum, baldcypress; Butia capitata, pindo or jelly; Livistona chinensis, Chinese fan; Phoenix canariensis, Canary Island date; Phoenix dactylifera, date; and Sabal palmetto, cabbage, sabal.

 

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Q: What can you tell me about the purple tube flower?

 

Purple tube flower

Purple tube flower

A:   I believe you are talking about Iochroma cyanea and it is a distant relative of the angel trumpets which are both in the nightshade family. Often these plants are called “mini trumpet plants.”  Like their cousins, all parts of the plant are poisonous. More than likely your plant will be a perennial, although it can be tender if temperatures stay below freezing for long periods of time. The purple tubular flowers are thin and grow 3 to 3.5 inches long.  It is a favorite of bees, butterflies and hummingbirds. There are several varieties with flower colors ranging from pale lilac to purple to red.  The full mature height of the shrub can be from 3 – 6 feet with a potential 4 foot spread.  Iochroma cyanea blooms repeatedly from late spring through the fall – which will make it my favorite shrub.  Here it is in the middle of October and mine is blooming.  Iochroma cyanea will need consistent watering during establishment but will be able to tolerate periods of no irrigation or rainfall once it is established. You can plant it in full sun but it will tolerate dappled lighting if it receives sufficient morning sun exposure. I have planted my shrub in dappled light as it may have problems with Florida’s intense summer heat and humidity.  Maybe I will report back to you after a few years and let you know how it did in my yard.  Most plants have to be pretty tough to survive – I don’t baby anything.  Iochroma cyanea can be propagated by seed.


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Q: How do I control whiteflies on my leafy green vegetables?

 

Whiteflies

Whiteflies

 A:  Whiteflies feed exclusively on leaves, nearly always occurring on the undersurface. They suck juices from the plants and also excrete large quantities of honeydew in which sooty mold grows. Leaves will be sticky if there are many whiteflies feeding on the leaves above them and may turn black with sooty mold which grows on the honeydew. The most common whitefly found on Florida vegetables is called the silverleaf whitefly (http://edis.ifas.ufl.edu/in286) because of the effect its feeding has on squash leaves. Feeding by the immature stages or nymphs can also result in white areas in tomato fruits, streaking of pepper fruits, and blanching of broccoli stems. Whiteflies are not flies but are distant relatives of aphids and leafhoppers and, like them, feed on plant sap with piercing- sucking mouthparts. Whiteflies can spread some plant viruses, such as tomato yellow leaf curl virus and bean golden mosaic virus. The adult is a very small (less than 1/16 inch long) and has white wings dusted with a waxy substance. It holds its wings like a tent over its yellow body (Figure 26). It lays its eggs on the lower surface of leaves of many plants, including tomatoes, eggplant, melons, cucumbers, squash, okra, beans, cabbage, and broccoli. Except for a very brief time after hatching, the nymphs cannot move on the plant and look like clear or pale yellow scales. Regular applications of insecticidal soap may help keep whiteflies under control. Tiny wasps also attack the whiteflies. Flowers planted around and in the garden may help these wasps and other beneficial insects survive by providing a source of nectar. Other general purpose garden insecticides that kill on contact may also be helpful but will harm the beneficial insects. Because the insects are found on the lower leaf surface, sprays must be directed there in order to be effective.


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Q: My large holly tree fell over after the storm, can it be saved?

Fallen TreeA:  Only trees recently planted or have a trunk diameter smaller than 4 inches should be staked or replanted if they have fallen over during a storm. Large or older trees need to be removed as they were most likely compromised anyway.  If the tree is small enough, prop it back up and do the following:  Keep roots moist but not wet. If the hole is holding water, this might not be the best site for the tree – consider moving it to another area. Trees and shrubs grow best in well-drained soil. Be sure the new hole is wide enough to hold the roots but never plant it too deeply.  The large roots coming off the trunk should be within the first few inches of soil. Remove any circling/girdling roots while they are exposed.  Remember the roots should be going away from the trunk of the tree like the spokes of a wheel.  Prune any jagged and torn roots.  Set the tree upright and fill the hole with native soil – do not be tempted to add amendments to the hole. Water the soil in as this will remove any air pockets.  Good rule is to water with 3 gallons of water per inch of tree diameter. This can be done 3-4 times a week for several weeks until the tree becomes established. In addition, this is NOT the time to add fertilizer.  We want the tree to put out new roots only – not new shoots or flowers. It would be best to stake the tree while it is vulnerable but only leave the stakes on for 6-9 months.  Be sure the cables do not cut or girdle the tree trunk.  Normally, we would not suggest you do any pruning on the tree canopy but remove any cracked or broken limbs at this time.  Remember we do not recommend painting over the wound of the tree – allow the tree to heal over the wounds. Keep grass as far away from the tree as possible – a best management practice all the time.  Mulch several feet away from the trunk – never allow mulch to touch the trunk of any tree. It may take several months to even a year for the tree to overcome the trauma of the storm.  Be patient.  Regarding palms – just remove any totally dead or broken fronds.  Fertilization should not be done again until March of 2017 using only 8-2-12.  Then reapply in June and September.