Should I fertilize my grapevines? 

It is generally not necessary for home gardeners to fertilize grapevines in Iowa. Our fertile soils contain adequate supplies of essential plant nutrients. Fertilization may actually be detrimental. 

Too much nitrogen promotes excessive vegetative growth and delays vine and fruit maturity.  Fertilize grapevines when plants exhibit weak growth or poor leaf color. Use a complete, low analysis fertilizer, such as 10-10-10. Sprinkle a half-pound around each grapevine.

Early spring is the best time to fertilize grapevines. Do not fertilize grapevines in late spring or summer. Late spring or summer fertilization encourages succulent, late season growth, which would be more susceptible to winter injury.

Several of the trees in my neighborhood suffered extensive damage due to the accumulation of ice and snow on their branches. Are there trees that are less susceptible to storm damage? 

Tree species do differ in their susceptibility to ice, snow, and wind damage. Trees susceptible to storm damage include silver maple (Acer saccharinum), river birch (Betula nigra), green ash (Fraxinus pennsylvanica), poplars (Populus spp.), pin oak (Quercus palustris), willows (Salix spp.), and Siberian elm (Ulmus pumila).

Trees that are less likely to be damaged in a storm include sugar maple (Acer saccharum), American hornbeam (Carpinus caroliniana), ginkgo (Ginkgo biloba), crabapples (Malus spp.), ironwood (Ostrya virginiana), white oak (Quercus alba), bur oak (Quercus macrocarpa), red oak (Quercus rubra), baldcypress (Taxodium distichum), and littleleaf linden (Tillia cordata).

In addition to tree species, the age of the tree, its condition and maintenance history also determine the extent of storm damage. Large, old trees with a structural weakness, such as trunk decay, are susceptible to storm damage. Trees that were not properly pruned when young and possess narrow branch angles also are susceptible to storm damage. 

During the recent storm, a split developed at the crotch of a large tree. Can I save the tree? 

Cables and braces can be used to reinforce split crotches in trees. If properly installed, cables and braces can prolong the life of a valuable tree. Since cabling and bracing are difficult, these procedures should be performed by professional arborists. 

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