Fertilizing about 2-3 times a season is the norm for evergreens, however, applying nutrients later on in the season, especially after about mid-July is detrimental.
Generally, evergreens grow better when soil pH is acidic; many nutrients may be unavailable to the plant when soil is too alkaline. Depending on rainfall, water evergreens through late fall. The best time to fertilize your evergreens is before new growth expands, around early April in Minnesota, up to about mid-July.
You gear up for taking care of your lawn in the early spring but did you know that fall is a great time to take that same caring approach by fertilizing your evergreens, trees and shrubs? At Ryan Lawn & Tree, we understand you can't plant a new tree or shrub and just expect it to grow and flourish.
Damage due to excessive fertilizer or rock salt applications generally appears as marginal leaf browning (brown edges or leaf tips) or leaf scorch on deciduous plants (they drop their leaves at the end of the season). On evergreen trees and shrubs needle tips will turn brown and become brittle.
The recommended combination is 10% of nitrogen, 8% of phosphorus, and 15% of potassium. These are known in common parlance as NPK 10-8-15 or NPK 10/8/15.
We also recommend Greenskeeper's Secret All Purpose Fertilizer for Vegetables, flowers, fruit, nut and shade trees and hardy evergreens and shrubs. For best results, use according to the following directions and water thoroughly after each application.
Helps strengthen your evergreen trees while ensuring they look vibrant and healthy. Contains essential nutrients that feed above and below the soil to create a double feeding action.
Since most of a tree's roots can be found in the top foot of soil, broadcast the fertilizer evenly with a rotary or drop-type spreader over the root zone area to fertilize the tree. Water after application to make the nutrients available to the roots.
Trees and shrubs that should not be fertilized include newly planted specimens and those with severe root damage from recent trenching or construction.
Evergreens. I fertilize evergreens in the early spring. I use one pound of 10-10-10 per inch of trunk diameter. If the diameter is over six inches, I use two pounds of 10-10-10 per inch of trunk diameter.
Regular, repeatable foliar applications or deep-root treatments can help protect your needled evergreens from infestation. Good cultural practices like watering in drought and mulching for soil moisture retention can keep your evergreens from becoming stressed and susceptible to disease.
Winter weather can cause damage to evergreens which results in the browning of foliage. The evergreen can be healthy in summer and fall, but when winter comes around the branches may gradually turn brown. This browning is due to winter burn caused by a lack of moisture in the air and dry winter winds.
For example, adding coffee grounds or organic matter around your evergreens' soil is a good place to start if you need to increase your soil's acidity. But it's not a good place to end. While your tree would get a tiny dose of nitrogen, it'd miss out on its phosphorus (P) and potassium (K) that it needs.
Prune all evergreens, except pine, before new growth starts in the spring or during the semidormant period in mid-summer. When pruning, follow the general branching pattern to maintain the natural shape. Remove dead, diseased, or broken branches anytime.
Surround your evergreens with a fresh layer of insulating mulch to regulate the soil temperature and seal in moisture. Once the ground freezes, the roots cannot replace lost water, and sun and wind can deplete it from the foliage, a double whammy for your evergreens.
Newly planted trees still in their development phase but after their first growing season needs to be consistently fertilized up to twice annually to help support their root establishment. Mature trees generally need lower amounts of nitrogen to keep their foliage and health in good condition.
Many experts accepted this timing for years. And although early spring is a good time, new research indicates there is an even better time. Now a majority of arborists consider late September or October a great time to consider a fall fertilizer for trees and shrubs.
Most importantly, tree fertilizer spikes inserted around a tree base leave your tree much more vulnerable to infestation from insects or tree diseases. These fertilizer spikes provide the perfect opportunity for insects to infest and damage the root system, which can lead to severe tree damage or even tree death.
Make the last fertilizer application before July 1.
New growth also needs time to "harden off" before winter. Tender new growth is at risk of cold injury if it is forced late in the season, when plants and trees should be shutting down for winter.
During a summer afternoon, up to half of the water can be lost to evaporation. The best time to water is in the morning or evening, so the roots have a chance to absorb most of the water.
As a result, trees usually respond best to fertilizer with a 2-1-1 or a 3-1-1 ratio (nitrogen-phosphorus-potassium). Commonly available fertilizers with a 2-1-1 or similar ratio are 18-6-12, 12-6-6, 10-6-4, 10-8-6 and 10-8-4.
Watering should take place every day for approximately 15-20 minutes, depending on the pressure in your system. Of course, if it rains that day, no watering is necessary. It is best to water in the evening or early morning when the sun isn't up.
'When fertilizing evergreens, it is best to use a product that is higher in nitrogen than phosphorous or potassium,' recommends Rachel. 'Evergreens respond more quickly to nitrogen-based fertilizer than they do other nutrients such as those provided by using eggs in the garden or using banana peels as fertilizer.
MG is so strong that if used incorrectly, the fertilizer will actually burn the leaves and roots of your plants (you may have already experienced this). Imagine what it's doing to the healthy bacteria, fungi and other soil microbes that are working so hard to provide the nutrients your plants need.
Care Tips for Evergreen Trees
When your trees are healthy, they'll grow faster. Most evergreen conifers require full sun, so plant them where they can receive at least six to eight hours of direct sun a day.