Fertilizing cedar hedges

(Question)

Hello,
I am preparing to fertilize my cedar hedges, for the first time, and need an advice from an expert. I have two different generations of cedar hedges: a line of 15 years old cedars, which is around 15 feet high, and a line of 3 years old cedars that are 8 feet high. All my cedars have grown up well, they are green and nice, but they are not as rich as I would expect. Someone told me they need to be fertilized. I know that this is an important and delicate operation, because by not applying them correctly, it might kill the hedges, which I don’t want to happen.

I intend to apply 30-10-10 water-soluble fertilizer, and I read about watering the soil around the hedges BEFORE pouring the soluble fertilizer, and also about watering the soil around the hedges AFTER pouring the soluble fertilizer. I am confused. I don’t want to burn the roots in any way, so which is correct ? And then,  the fertilizer package  indicates on how much fertilizer to put in water (the ratio) to be dissolved, but it doesn’t say what quantity I should pour around one tree, also taking into consideration that I have two different generations of cedars. So what quantity of liquid should I pour around a 15 year cedar, and what quantity for a 3 year cedar ?

Thank you very much

(Answer)

 

The most popular choice for vertical cedar hedges in Ontario is the Emerald Cedar, which can grow robustly handsome. If this is the case, it sounds like you are enjoying both your senior, and junior, plantings.  You mention that your cedars are “not as rich” as you expect. If you’re referring to the density of the growth, it is typical for cedars to “brown” from the inside out, as they grow in height and breadth, from year to year. This fallen leaf matter provides valuable nutrient compost, and moisture maintenance, at the base of the cedars. Natural “die-back” can average about 30% a year. However, if you mean that the leaf colour is not as rich as before, then perhaps you might want to gently enrich the soil, as you’ve mentioned. Generally speaking, however, cedars do not require much, if any, soil amendment, knowing that the root system spreads outward on each side, at twice the radius of the tree, accessing ample nutrients. But, if you sense that the leaves look pale, or unhealthy, then the addition of nitrogen and iron could possibly help.

You could choose a combination feeding of an organic granular mix of  bone and blood meal.  Or you could spread organic compost around the base of each tree trunk, then cover with a layer of moisture-retaining mulch, set back about six inches from the base of the trunk.  In order for liquid fertilizers to be best absorbed by plant roots, the nutrients must be able to be absorbed via the existing soil. Fertilizers are concentrated salts, and can damage plant roots if applied on dry soil. So, to answer your question: first slow-soak the soil around your cedars’ roots with water, before applying the fertilized solution, to make  the soil absorbent. Then, prepare a bucket  full of 30-10-10 nitrogen-rich  solution exactly as directed, and apply. Lastly, be sure to water thoroughly with an equal amount, after applying the fertilizer, but slowly, and gently, so as not to wash the nutrients away. All of your cedars can be fertilized in the same manner, regardless of age:  the key is to mix your solution as per the receipe, and apply to water absorbent soil, and give a good drink afterwards. Salut !

References:

http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=43010

www.landscapeontario.com