Research in woody plant nutrition has shown however that nitrogen is the element that yields the greatest growth response in trees and shrubs. For this reason, high nitrogen fertilizers with N-P-K ratios of 4-1-1, 3-1-1 or 3-1-2 are generally recommended for feeding established woody plants.
Feed trees, shrubs and hedges with a balanced fertiliser (such as Growmore or blood, fish and bone), sprinkling it over the root area before hoeing into the soil surface. This will particularly benefit young, weak, damaged or heavily pruned plants.
Using rotting stuff like compost, leaves, or wood chips feeds the critters that live in your soil. This mimics how trees get nutrients in the forest which means that it is sustainable and doesn't have any accompanying harmful impacts of store-bought fertilizers.
I would use an all-purpose fertilizer around trees and shrubs. Such products have equal amounts of each of the primary nutrients (nitrogen, phosphorus, and potassium). Examples that you can find in box stores are: 10-10-10, 13-13-13, etc.
When it comes to fertilizing trees and shrubs, arborists often recommend deep root fertilization. Deep root fertilization is a specialized type of fertilizer application method used to help restore trees that are struggling or showing signs of decline.
Fertilizing Your Trees
Like all plants, trees need adequate nourishment to grow. Potassium, nitrogen, and phosphorus are the primary macronutrients that trees need to flourish.
Trees and shrubs that should not be fertilized include newly planted specimens and those with severe root damage from recent trenching or construction. The root systems of these plants need to re-establish before fertilizers are applied. Older, established trees do not need to be fertilized every year.
Nitrogen, phosphorus, and potassium are needed in larger amounts than other nutrients; they are considered primary macronutrients. Too much fertilizer is not only a waste of money, but it can damage plants and harm the environment.
To make compost, take all your scraps (like eggshells, fruit peels, and coffee grounds) and put them into a pile with leaves, sticks, and other organic debris. Overtime, the microbes will break the pile down and turn it into fine fertilizer, which you can mix into your soil.
Trees do best with infrequent, deep waterings. Prune trees only when it is necessary for structure, health, and safety purposes. Remove vines, turf, or competing vegetation surrounding the tree's trunk.
Phosphate also helps to encourage blossom and fruit development once fruit trees mature. Potassium (the last number) helps to regulate metabolism and other processes within the tree. The best time to fertilize fruit trees is during the growing season, starting in early spring (around bud-break) and finishing by July.
If you have a variety of trees and shrubs in your garden, you can use an all-purpose plant food like Miracle-Gro® Shake n Feed® Flowering Trees & Shrubs Continuous Release Plant Food which will feed for up to 3 months.
Nitrogen helps produce green leaves and stems, phosphorus helps produce root development, and potassium helps the plant withstand stress from heat or cold. A good all-purpose fertilizer would be a 10-10-10 NPK (nitrogen, phosphorus, and potassium). This type of fertilizer will work well for most plants and soil types.
Research in woody plant nutrition has shown however that nitrogen is the element that yields the greatest growth response in trees and shrubs. For this reason, high nitrogen fertilizers with N-P-K ratios of 4-1-1, 3-1-1 or 3-1-2 are generally recommended for feeding established woody plants.
An economical and effective method of fertilizing trees and shrubs is to broadcast a granular or pelletized fertilizer over the entire root zone area. Use a drop-type or cyclone spreader to distribute the recommended amount of nutrients evenly (Fig. 9). Follow the manufacturer's instructions on the label.
Fertilizers. Too much or too little fertilizer can be bad for your dying tree. Soils with organic fertilizers can help an area around a tree remain loose, giving the root system plenty of room to breathe. This will allow your tree to get the extra nourishment it needs.
When applying fertilizer, always read and follow all label directions carefully - too much fertilization can permanently damage trees and plants. Excess fertilizer alters the soil by creating too high of a salt concentration, and this can hurt beneficial soil microorganisms.
Give them the freedom to grow
The ground around the base of a tree might look strong enough to serve as a barrier between the air and the tree roots, but it's important not to stack heavy things, have high foot traffic, use a lawnmower too close, or use anything but a thin layer of mulch around the tree trunk.
Deep root watering slowly carries water into the ground instead of getting the surface wet, which helps improve tree growth rate. This will save you time and money, all while making your tree grow at an impressive rate.