Spring care of Junipers

(Question)

Caring for juniper trees and shrubs in the spring
When this spring do I remove the burlap I have put around juniper trees and shrubs and when do I fertilize these junipers? I have also been given conflicting info about what type of fertilizer to use – the sticks you put into the ground (and can use into the summer) or a general shrub fertilizer? I used the fertilizer sticks last year but started late with it. Now I am told that method is not done so much any more and that the shrub fertilizer is used instead. If so what type of shrub fertilizer and what are the three numbers of the fertilizer.

(Answer)

Spring garden clean-up including the removal of any protective wrapping on plants can begin as soon as the soil is dry enough.  Our online spring clean-up gardening guide (link below) describes this condition as – “it should crumble in your hands, not stick together in clods”.

https://www.torontomastergardeners.ca/index.php/factsheet/spring-clean-up-a-toronto-master-gardener-guide/

There may not be a need to fertilize your shrubs on an annual basis. The addition of any soil nutrient is recommended only if soil tests or observation indicates a deficiency.  Pale green, undersized leaves, reduced growth rate or plants recovering from insect attacks or disease are all examples of when fertilization is warranted.

A complete fertilizer contains the 3 major plant nutrients: nitrogen (N), phosphorous (P) and potassium (K).  The numbers you asked about are the percentage by weight of each of these nutrients contained in the fertilizer.  This is called the fertilizer grade or analysis.  When a complete fertilizer is used on shrubs, the ratio of N-P-K should be approximately 3-1-2 or 3-1-1.  Examples of fertilizer grades with these ratios are 15-5-10 and 15-5-5.

Slow-release fertilizers are recommended to avoid burning plants with an overdose.  They are also more environmentally friendly as only a small amount of nitrogen is released at a time.  Excess nitrogen will leach through soils and pollute ground water.  Look for a fertilizer that has at least 50% water-insoluble nitrogen.

The easiest way to apply fertilizer to shrubs is to broadcast over the root zone area of your shrubs.  Follow the instructions on the fertilizer package to determine how much fertilizer to apply.  To read more about, fertilizing trees and shrubs check out an article produced by the University of New Hampshire Co-operative Extension at the following link:

https://extension.unh.edu/resources/files/resource000590_rep612.pdf

Organic materials such as compost and manures are natural slow-release sources of nutrients with the added advantage of improving your soil structure through the addition of organic matter.  These materials can be used on a regular basis and in relatively large quantities because of the low percentage of nitrogen they contain.  To learn more about organic fertilizers, have a look at our gardening guide, “Organic Fertilizers: the Basics” at the link below:

https://torontomastergardeners.ca/wp-content/uploads/2012/07/Organic-Fertilizers-Basics.pdf