Sunday, June 9, 2013

Fertilizing Shrubs and Trees

Blueberries  (from blueberry seminar – see blog)
  • Fertilizer - use ammonium sulfate, NOT aluminum sulfate. Be careful here!
  • Yellow leaves indicate an iron deficiency and high pH.
  • Do not need to fertilize the first year; second year - use ammonium sulfate, 2 oz. per bush; mature plantings - use ammonium sulfate, 8 oz. per bush or 1/2 lb. cottonseed meal per bush.
  • Fertilize in spring or early summer, BEFORE JULY 4.  Avoid winter injury by not fertilizing after July 4.
  • A dose of acid-based fertilizer in late fall will give the plant a good start on the growing season. Adding a good layer of compost helps fertilize the plant and adds organic matter to the soil.
Lemon Trees
  • Citrus tress need to be fertilized. They are heavy feeders and need adequate levels of fertilization in order to obtain adequate growth and production.
  • The amount of fertilizer applied to a citrus tree depends on the size of the tree and how much fruit it produces.
  • It is best to fertilize all citrus trees with a special citrus fertilizer that contains minor elements like magnesium, manganese and baron. However, if such a fertilizer is not available, use a common 6-6-6 general fertilizer. As long as the mature leaves are healthy, showing a good deep green color and full size, continue with your program.
  • Occasionally, the leaves will show yellow patterns. When this occurs, use a complete nutritional spray that can be found at most garden supply stores. It will generally contain zinc, manganese and boron. Some will also contain copper.
  • Fertilizer Program for young trees: The following recommendations are based on an 8-0-8-2-0.5-0.1 citrus mix fertilizer. Do not fertilize trees recently planted until new growth starts. Fertilize according to instructions on package when the new growth appears; then, each six weeks thereafter, until October. Do not fertilize young trees after October.
  • Application rates for fruit bearing trees: Be consistent and fertilize about the same time each year, make four applications as follows: First in March; second in May; third in August and fourth in October. The amount of fertilizer to use at each application can be determined by a simple method. Measure the tree trunk circumference in inches at its greatest point near the soil level and divide that number by the number of applications per year (four applications suggested). For example, a tree measuring 20 inches in circumference needs 20 lbs of fertilizer per year. If four applications are used per year, then 20 divided by four will make 5 lbs of fertilizer per application.
  • Using  5-10-5 fertilizer and three applications; the first in mid to late May (for spring planted roses the fertilizer should be applied after new green vegetative growth begins), the second in mid-July, and the third in the autumn after a killing frost, or very early in the spring before new growth begins.
Azaleas and PJM’s (rhododendrons)
  • Rhododendrons and azaleas benefit from an annual fertilization.
  • Apply the fertilizer either in late autumn after a hard freeze has occurred, or in the early spring.
  • Regardless of the type of fertilizer used, no fertilizer should be applied after the first week in June. Fertilizer applied after this date may spur late season growth that does not have sufficient time to harden before freezing temperatures occur in the fall, and late growth will likely be burned or killed.

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