In the forest, soil nutrition comes from decaying organic matter on the ground, but in urban and suburban environments, soil composition and water drainage has been significantly disturbed, and gardens and yards are cleaned of organic debris. This is why tree and shrub owners might consider using fertilizers annually or as needed. Choosing a fertilizer wisely can help you maintain a healthy landscape in a timeframe, budget and method that best suits you.
When shopping for a fertilizer, there are 3 things to decide on:
1. Ratio of N-P-K. Each macronutrient (Nitrogen, Phosphorous and Potassium) promotes different plant reactions, which is the significance of the numbers. Fertilizers with higher rates of Nitrogen encourages abundant new leaf growth, high Phosphorous encourages root growth and Potassium encourages drought tolerance and winter hardiness. For these reasons, Fertilizers that are high in N are applied in the spring and high in K in the Fall.
2. Synthetic/Chemical or Organic. Organic Fertilizers have lower N-P-K amounts than Synthetic ones. Organic fertilizers are made from composted organic materials like fish, blood, manure, etc. and can increase soil activity and structure. Synthetic fertilizers are fast acting and are sometimes blended with pesticides or have other engineered properties such as slow release biodegradable capsules.
3. Granular or Liquid formulas. Granular may be a good choice if you already have a spreader handy, whereas some liquid products are available that you can attach onto your hose end for easy spray application.
*Always follow application rates on products to avoid pollution, plant injury and/or pest problems.
The short answer is NO. Many people have seen or heard of wound sealants and wonder if they should be using them for the tree’s health. The tree care industry has done a 180 on this topic, from advocating to discouraging their use, which has confused many. This was a common practice decades ago; old tree care texts recommended it and sealant products are still sold at many garden centers. Many substances had been used from roofing tar to latex house paints. It was believed that using these on trees kept out fungi after a cut exposed its vascular tissues.
Research has since shown that tree cuts need open air to trigger natural wound sealing properties. Trees contain chemicals that inhibit fungi and resist decay in the area where a branch meets the main trunk. This area, called the branch collar, is where we are supposed to make our final pruning cut when removing a branch for this very reason. Therefore, the best way to guard against fungi and decay development is to make accurate and judicious cuts and let them breathe.
Deciding when to prune/trim is confusing to many people because there is no one-size-fits-all answer and even the experts can’t always agree. Yet, it is the most commonly asked question of gardeners, landscapers and arborists! Pruning of live branches is not as critical as many people think, but it is worthy of discussion.
The Best Times for Pruning: (the opposite of Part 1; Worst Times)
In general, the optimal times for ornamental tree and shrub trimming is early spring and summer and those should be the go-to times if you are unsure. Don’t let timing keep you from grabbing your pruners if a haircut is truly needed and you just can’t wait!
If you are trying to figure out the best time to prune/trim, start first with the worst times to prune (because more experts agree on these) and work backwards from there.
So, what are the worst case scenarios in pruning at the ‘wrong time’?
One important point is that pruning at the “wrong” time of year probably won’t kill your tree or shrub, but it may weaken it in the long run. Indeed many plants are trimmed at less than ideal times and yet they survive.
The Worst Times for Pruning:
To be continued in When To Trim, Part 2.