When And How To Use Evergreen Tree Fertilizer

Evergreen is a combination of two words: ever and green. Thus, evergreen means an everlasting green plant. Unlike most plants, an evergreen retains its foliage throughout the entire year. Evergreens do not shed their leaves in one go at the onset of cold weather because they can store enough water for survival throughout the winter.

Evergreens shed and grow leaves continually throughout the year, making the foliage appear consistent from season to season. If a plant is not considered evergreen, it is deciduous, which means it sheds all its leaves according to seasonal environmental changes, usually all at once or over a relatively short period. 

Misconceptions about Evergreens

Many think this term means the plant foliage must be green to be considered evergreen. The foliage could be blue or golden but is constant rather than changing seasonally. Many also have the bonus of flowers.

Another misconception people have is evergreens and conifers are the same thing. Conifers mean cone-bearing, a reference to the way they multiply, while evergreens refer to the leaves. Conifers reproduce via their cones, which contain their seeds, and most are evergreen, but not all evergreens are conifers. 

Types of Evergreen Plants

• Conifers: Coniferous trees have needle or scale leaf types that are more weather tolerant than broad, flat leaves but less effective. There are over 600 species, from dwarf firs to giant trees such as the Himalayan Cypress. 
• Broadleaf Evergreens: Shrubs or small trees having dense, large, green leaves, such as holly, azalea, and silver oak. Some of these plants produce berries, and others bloom in flowers.
• Tropical Evergreens: They are found in warm, humid climates, such as rainforests and tropical regions. Examples include banana plants, palms, cycads, and rubber trees.
• Vines and Ground Covers: These quick-spreading plants are perfect to carpet the ground with something other than grass. Popular ones include ivy and creeping juniper, often used for landscaping.

Reasons for Planting Evergreens

Planting evergreens on your property has environmental and economic benefits. The trees serve as wind shields, keeping the cold wind at bay and preventing it from entering the house through gaps and cracks, especially with poor insulation.

Many people rely on larger evergreen trees like the native white pine, white spruce, or eastern white cedar to prevent snow from piling up around their houses, which helps them save on heating bills. The rippled and dense foliage of native evergreens also supports many overwintering birds and other cold-active wildlife.

Perhaps the best reason for planting evergreens might be the beauty they bring to your landscape when plants are dormant in the winter. Deciduous plants become barred and brown, making your garden look lifeless. Meanwhile, evergreens bring their green vibrancy, adding back life to your property. 

Timing is critical in fertilizing evergreen plants. So, when to fertilize trees and shrubs? This will depend on two factors: the condition of the plant and the season.

Season

The ideal time to give evergreen food is early spring before new growth expands. During this period, plants come out of dormancy after a harsh winter and become active. They need slow-release fertilizers with essential nutrients for building strong roots and fresh, healthy foliage. 

If you miss the early spring window for fertilization, late spring to early summer is an effective alternative. This way, you can be sure the evergreens are fed because they are actively growing even in late spring or early summer and need nutrients to support the growth. The roots are expanding, and new foliage is developing, so they will benefit from additional nutrients.

Condition of The Evergreen

Besides the season, there are a few key signs to look for when it comes to knowing when to fertilize your evergreen plants. If you are growing evergreens in your garden, look out for uncharacteristically slow or sparse growth and needles losing color and turning brown or yellow. These are tell-tale signs that your plant could do with a boost from fertilizer. 

However, poor growth does not always indicate your plants need fertilizer. Stress from heavily compacted soil, disease, weeds, freezing, or scorching weather can also cause slow growth. You need to identify whether the fertilizer is the key to improving the plant's condition. Identifying this may be difficult, but in the absence of pests, temperate weather, or well-tilled soil, adding fertilizer is the best place to start combating your plants' problems.

Fertilizer may also help when growing evergreens in a less-than-ideal site, such as very sandy or heavy clay soil, and you wish to encourage more rapid growth in relatively young evergreens.

When Not to Apply Fertilizers

Do not apply fertilizer during peak summer and fall, as this will stimulate new growth late in the season. This new growth may not mature in time to develop a protective layer. As a result, they may not have time to acclimatize to colder temperatures and are much more likely to suffer winter injury and dieback. 

Additionally, fertilizer should never be applied to drought-stressed plants as they contain salts that abstract water from the plant and burn the stressed roots. It also forces new growth when the plant should be devoting all resources to survival. These conditions make it more likely to die. Besides, stressed and sick plants cannot take the nutrients of fertilizers, which remain unused in the soil, only to harm the plant later.

When you go to the store to buy fertilizers, you will be spoilt for choices, but that is not good news. Usually, fertilizer brands attach the tag 'best fertilizers for evergreen trees and shrubs' to their product. This makes it quite confusing when deciding which one to pick. However, here are some factors to consider when choosing the right one. 

The safest choice would be to buy a branded fertilizer containing nitrogen, potassium, and phosphorus in the proper ratio. These are bunched under a common name: “NPK”. Each of these letters indicates the chemical names of the nutrients nitrogen, potassium, and phosphorus used, respectively. You might also want to check for trace elements such as rock dust and calcium. 

Price

Price matters when it comes to fertilizer. You can spend as much or as little as you want, but the outcome will be what you paid for. Cheaper fertilizers contain an inferior class of all components, do not dissolve well in water, and may wash away without entering your plant. They may also contain traces of harmful chemicals that damage your plants.

Soil pH

The best fertilizer will be one that compensates for the pH levels of the soil. All evergreen trees grow best in slightly acidic soils with a pH of 7.0 or upwards. Sometimes, you might have only basic soil around you, which means it is too alkaline for evergreens to thrive.

In such instances, have your soil tested by a lab before deciding whether or not your evergreens need fertilizer, as the wrong soil pH value may hinder the plant’s ability to access the fertilizer nutrients.

The amount of fertilizer to use is influenced by plant species, plant size, growth stage, and the fertilizer type. Here is a simple guide

Typical Dosages by Plant Type:

Small Plants

Since small plants do not have deep roots like bigger plants, nutrient uptake is also lesser. Hence one tablespoonful of granular fertilizer or ¼ cup of liquid fertilizer diluted in water would be sufficient for each plant. Anything more cannot be handled by the plant and causes more harm than good. The roots may burn or new growth may be weaker.

Medium Shrubs 

Medium shrubs have larger roots and require more nutrients than smaller ones. Apply liquid fertilizer according to directions or 1/2 to 1 cup granular fertilizer around the base of the shrub so that nutrients will be quickly absorbed. Overapplication of fertilizer will cause rapid but weak, overly tender growth, increasing the risk of frost damage. 

Large Trees and Evergreen

Large trees and evergreens require more nutrients to support their wide root systems and dense canopy. Proper fertilizer applications will yield vigorous growth and make the plants or trees resilient to stress factors like pests or drought.  Small doses of fertilizer applied throughout the growing season will improve the growth and health of the plant. 

Distribute 2 to 4 cups of dry fertilizer along the drip line, away from the trunk. Another method to feed plants would be to use the spray applicator or tree feeding system with diluted liquid fertilizer for wider area coverage.

General Tips:

• Always read the label on the bag as it will have instructions on using it based on the nutrient concentration.
• The amount of fertilizer you use depends on the plant condition, soil, and whether it is slow-release or fast-acting.
• After fertilizing, water the plants to allow nutrients to dissolve into the soil so plant roots can access it. 
• Do not apply fertilizers too closely to stems or trunks to avoid injury.

If you want to get technical, you can use formulas to calculate fertilizer rates. This calculation ensures you are using the right amount of fertilizer for your evergreens and not in excess, which results in overfertilization. Most of the time, fertilizers are recommended in pounds per 1,000 square feet. 

Among the three macronutrients, nitrogen is crucial for its relevance in vegetative growth. Thus, the fertilizer application rate is calculated based on the nitrogen content of the fertilizer.

For most evergreen plants, an annual maintenance application of 1-3 lbs of actual nitrogen per 1000 sq is recommended. This rate will now allow you to estimate how much nitrogen fertilizer to apply if you know the square feet area your plant occupies.

To determine the pounds of fertilizer to apply, read the NPK label on the bag and determine the percentage of nitrogen in your fertilizer. Then, calculate the amount of nitrogen in the bag with this formula: 

% of nitrogen X weight of the fertilizer bag

So, if you bought a 10-10-10 formulation of a 20-pound bag, you know it has 10% nitrogen. 10% of 20 is 2, which means the entire bag contains 2 pounds of actual N. If we know the standard rate of fertilizer application is 1 pound of nitrogen per 1000 square feet, then a 25 feet plant needs: 

(Standard rate/ the area you are fertilizing) X pounds of nitrogen in the bag
(1/1000 X 25) X 2= 0.05 

You need 0.05 pounds of fertilizer or roughly 1/10 of a cup for 25 square feet.

There are a few ways to add fertilizer to an evergreen plant. 

Drop Spreader

You could use a drop spreader to fertilize under the evergreen branches and slightly beyond and then soak it in, as long as the rate is two pounds of nitrogen per 1,000 square feet or less.

Anything more than that will burn the grass the fertilizers spread onto, even if watered immediately after application. In the case of mulched trees, spread the fertilizer over the mulch and water it well. The granules will dissolve to the soil surface.

Fertilizer Holes

A more effective fertilizer application would be to dig holes and refill them with the fertilizer. Soften the soil for easier digging by thoroughly soaking the area you want to fertilize, ensuring the moisture reaches several inches deep into the soil. Then, using a crowbar, soil auger, metal rod, or other tool, make holes approximately two inches wide by eight to twelve inches deep.

Do not dig the holes haphazardly if you want the fertilizer distributed evenly throughout the root zone. The holes should start about 1.5 feet away from the trunk of small trees to avoid damaging the trunk or shallow roots and 3 feet away from the trunk of mature trees. The holes should be about 2 feet apart in large concentric circles.

Divide the amount of fertilizer needed according to the tree size, place it into each hole, and water the area. You can leave the fertilizer open without covering it with soil. This technique improves airflow to the roots and ensures water can dissolve the fertilizer and carry nutrients down to the root zone more efficiently.

Fertilizer Spikes or Root Feeders

Fertilizer spikes are a convenient way of fertilizing evergreens and work well if applied sufficiently. However, they are less cost-effective than granular products since each spike contains only a small amount of fertilizer.

Root feeders are another option. They can apply liquid fertilizer on all soil except heavy, poorly draining soils. However, it can be inconvenient when applied to light, sandy soil since it’s a lot of work. Liquid fertilizer leaches quickly through sandy soil and requires several applications during spring and early summer. Additionally, root feeders, like fertilizer spikes, are more costly than standard granular fertilizer.

In addition to fertilization, evergreen trees and shrubs would benefit from applying mulch to the soil surface under their branches and perhaps a few feet beyond. It prevents water evaporation, insulates the plant roots from extreme heat and cold temperatures, encourages beneficial soil organisms, and provides them with nutrients.

Evergreens are mulched with wood chips or shredded bark. However, any mulching material will do. Well-rotted manure or seasoned compost will add a small amount of nutrients as they break down further. The mulch ring should start where the main tree roots point away from the trunk and continue out from the tree trunk at about three or four inches deep. The mulch should be deep enough, or about 3 to 4 inches, around trees and shrubs to prevent weed growth and add organic matter to the soil as it breaks down.

Never lay plastic sheeting under any mulch, as it will prevent water from reaching the tree roots. Landscape fabric or “weed barriers” are not recommended under organic mulch like shredded wood. They should only be used under non-organic mulches such as rock and shredded rubber to prevent these materials from penetrating the soil.