Broad Leaf Evergreen Plants
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Oregon grape, Ivy, Rhododendrons, Holly, Boxwood and Laurel are a few of the many plants that fall into this category.  Nearly all broadleaf evergreen plants are acid loving and require sufficient amounts of iron (we recommend Hi-Yield “Iron Plus Soil Acidifier” or Ferti-lome "Iron with EDDHA) to maintain a healthy, dark green texture.  Applying ten to fifteen pounds of product per thousand square feet three times per year is advisable.  During the cooler spring and fall months, Ferti-lome “Liquid Chelated Iron” is a quick and safe way to obtain a lush green effect, but applying Liquid Chelated Iron may burn plants once temperatures reach 80 degrees or more.  Keep this product off cement since iron cal stain concrete. 

Several varieties of broadleaf evergreens produce colorful blooms and need regular feeding to bloom the following year.  Use Ferti-lome “Azalea, Camellia, Rhododendron Food” for all blooming broad-leaved evergreen plants.  Apply a light application every three to four weeks starting in mid-February and continue through mid-June.  These frequent applications allow the plant to produce at its fullest extent without lapsing in the nutrients needed to maintain a healthy condition.  Many blooming evergreen plants produce buds immediately after blooming for the following year.

Only light pruning is required on most broad-leaved evergreens.  A few evergreens require light pruning several times after blooming to maintain shape.  Do not prune too late in the season however or you may remove some if not all of next year’s blooms on plants such as Rhododendrons.

During extremely hot summer months, it may be necessary to spray broad-leaved evergreens with an anti-desiccant.  On a hot summer day, the plants root system may be unable to keep up with the plants ability to transpire water.  This is especially common then soil temperatures are high.  Applying an anti-desiccant slows the water loss process.  Pay particular attention to broadleaf evergreens during our hot summer months and again during cold winter months.

When leaf tips and/or the edges of the leaf begin to turn brown or die back, it’s likely that not enough water being applied to the plant.  This is the tenderest part of any plant and is the first part to be effected when there is a shortage of moisture.  If the center of the plant starts to die, then the plant may not be fertilized properly.  There are several causes regarding this scenario, but the most common is too much nitrogen.  The second most common cause is alkaline soil.  A nutrient deficiency can cause the entire plant to turn yellow, sometimes caused by a lack of magnesium, iron, sulfur or a combination of these elements.

Spray broadleaf evergreens with an anti-desiccant during the winter months.  You might ask, “How does this help my plant since it’s dormant?”  Anti-desiccant’s seal the leaves and slows moisture loss.  During cold months, the soil freezes and moisture may not be available to the plant.  When the winter sun shines and especially when snow is on the ground, plants leaves can transpire water and without available replenishment of water, the leaves die.  Leaves are very slow to come back on broadleaf evergreens and may take several years before the plant looks healthy again.  Apply an anti-desiccant to both the upper and under sides of the leaves.  Spraying the topside of leaves after each snowstorm will wash anti-desiccants off leaves. Normally, applying an anti-desiccant to the underside of the leaves once or twice each season is sufficient since water is less likely to get to the undersides of leaves.

Don’t be extremely concerned when broadleaf evergreen plants lose a few leaves in the fall.  This is a natural occurrence, particularly for rhododendrons and a few other broad leaf evergreens since they may lose the oldest set of leaves.

There are very few insects that attack broadleaf evergreens.  Black vine weevil is the most prevalent in the Treasure Valley, but they don’t limit themselves just too broadleaf evergreens.  Look for notches in the leaves of all plants.  Although the notches they chew in the leaves don’t really harm most plants, the damage they do to the root system certainly does. Don’t expect to find them during the daylight hours since these insects are nocturnal.  Apply Bonide Liquid Insect Control to eradicate these and many other insects in the garden.  A few homeowners may experience problems with whiteflies, but if you are spraying for black vine weevil, Bonide Liquid Systemic Control will help eradicate this culprit also. 

Spider mites are quite common in our area.  These small creatures are often about the size of a speck of dirt.  Gardeners who find cobwebs on plants are more likely seeing common spiders in the landscape than the possibility of spider mites.  Spider mites damage plants by sucking moisture from leaves or needles.  Spider mites start in early to mid-spring but the result of their damage often doesn’t show up until summer or early fall.  Check for spider mites by placing a white sheet of paper under a few branches and shake each branch vigorously.  Hold the paper still and watch for these very small mites to move.  If you have had problems with them in the past, apply Bonide Liquid Insect Control every 30 days starting in late spring as a precautionary measure.  Once they have damaged a broad-leaved or conifer plant, it may take several seasons to recover.

Since many broad-leaved plants are on the North or East sides of a home, moisture can become a problem.  In some cases root rot may occur.  Should this happen, apply Ferti-lome F-Stop Lawn & Garden fungicide to the soil according to instructions listed on the label.  

Since many of our broadleaf evergreens store moisture in the leaves throughout the year, you must “harden-off” these plants in the fall.  This allows them to survive our winter months without as much stress to the plant.  To do this, start reducing the amount of water to the plant in mid-fall.  Cut water off to the plant entirely until the leaves start to droop.  After this, water heavily again for several days followed by another reduction of water until the leaves droop slightly and then repeat heavy watering.  This should cause the plant to harden off and often increases survivability.  Water all shrubs and trees extensively as they near the end of the growing season. Plant survival may depend on how well the plant was watered late into the season.

Rhododendrons: A favorite…One of our favorite evergreen plants are rhododendrons.  They have spectacular blossoms, attractive foliage, and a wonderful fragrance.  Rhododendrons come in a huge assortment of sizes, colors, and shapes.  From this vast assortment, we are somewhat limited in our area because of climate conditions. Be cautious when planting, paying attention to location, light conditions and winter protection.  Never plant a rhododendron in direct afternoon sun.  The best location is one where the plant is shaded by 1:00 p.m.

Rhododendrons do best in acidic, moist, humus-rich, well-drained soil.  A preferable pH is between 5.6 and 6.2.  It’s important to apply Hi-Yield “Iron Plus Soil Acidifier” three times per year at the rate of ten to fifteen pounds per thousand square feet to lower alkalinity. 

When planting, we recommend digging a hole twenty-four to thirty inches deep and wide.  Mix 1/3 sand, 1/3 peat moss, and 1/3 topsoil together and use as the medium for planting.  Next, place about one foot of rock (gravel will work just fine) in the bottom of the hole.  Cover the rock or gravel with a piece of weed fabric to keep soil from filtering into the rock.  The rock or gravel allows excess water to dissipate from the root system.  Fill the hole to the proper depth, (to a depth where the top of the root system is slightly above ground level after backfilling is completed) and then fill the hole with water.  Now add Ferti-lome Root Stimulator to the water and set the rhododendron in the hole containing the water and Root Stimulator mixture.  Adding Ferti-lome “Chelated Iron” at the rate of 2 tablespoons per diluted gallon of water will free up chemicals and allow absorption into the root system.  Allow the rhododendron or other broadleaf plant to set for approximately twenty-five minutes in this solution.  Should the water dissipate into the soil, refill with water only.  The next step is to backfill using the mixture described above.  Carefully step around the plant to remove any air pockets that might exist.  Apply Ferti-lome Root Stimulator around the plant again after 30 days.  The best and easiest way is to pour approximately 15 to 18 tablespoons into a watering can, add water and then slowly pour the solution around each plant.

Mulching broadleaf plants is critical since the roots are typically shallow.  Apply three inches of bark mulch around these plants for best results.

After the rhododendron has flowered, deadhead it back at a point where the brittle flower is attached to the main stem of the plant.  This allows the plant to send its energy back into the plant instead of producing a flower seed.  Doing so will also increase the number of leaves on the plant.

In the information above, we described how to plant and care for a rhododendron.  Most broad-leaved evergreen plants (as well as many other shade loving plants) will benefit immeasurably when you follow these directions.

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