Boxwood Watering Tips – How And When To Water Boxwoods
By: Mary H. Dyer, Credentialed Garden Writer
Boxwoods provide leafy, emerald green color to the landscape with a surprisingly scant investment of time and effort on your part, as boxwood watering requirements are minimal once the plant is established. Read on to learn about watering a boxwood and when to water boxwoods.
Watering Boxwood Shrubs
Water a newly planted boxwood shrub deeply and slowly to ensure the roots are thoroughly saturated. After that time, water regularly until the plant is well established.
As a general rule, one or two deep waterings per week is plenty during the plant’s first year, decreasing to once per week during the shrub’s second growing season. Thereafter, watering a boxwood is necessary only during periods of hot, dry weather.
The plant may need more water if your soil is sandy, if the shrub is in bright sunlight or receives reflected sun from a nearby sidewalk or wall.
Boxwood Watering Tips
Give your boxwood a deep drink of water before the ground freezes in late autumn or early winter. This helps alleviate any cold damage that may occur from lack of water.
Watering a boxwood should be done with a drip system or soaker hose. Alternatively, allow a hose to trickle slowly at the base of the plant until the ground is thoroughly saturated.
Keep in mind that a large, mature boxwood shrub requires more water to saturate the root system than a small or young plant.
Avoid watering a boxwood shrub if the soil is still moist from the previous watering. Boxwood roots are near the surface and the plant is easily drowned by watering too frequently.
Don’t wait until the plant looks wilted or stressed. If you aren’t sure when to water boxwoods, use a trowel to dig 2 to 4 inches (5-10 cm.) into the soil at a point under the outer branches of the plant. (Be careful not to damage the shallow roots). If the soil is dry at that depth, it’s time to water again. In time, you’ll learn how often your boxwood shrub needs water.
A layer of mulch will conserve moisture and reduce water requirements.
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Maintaining Your Boxwood Shrubs
When it comes to hedging, boxwood shrubs are one of the most popular choices in landscaping. The dense, attractive foliage makes it an ideal species for hedges. Boxwoods will grow well in full sun areas, but also benefit from partial shade. Well-drained soils that are moderately acidic are best for growing. You can grow the shrub in containers or outdoors. Following are some tips to help you maintain your boxwoods.
Boxwoods don't require much watering once they are well established. Apply water frequently in the early growing phase, during dry weather conditions and in the late fall before the ground freezes for winter. Avoid over-watering, as this will stress the plants. Boxwoods have shallow roots and are easily overwhelmed if given too much water, as it will create drenched soils. Roots will experience difficulties in breathing and may suffer from suffocation.
Mulching helps to maintain cool soil conditions, which the boxwood prefers. Apply about 4 inches of mulch in the summer. You can increase this to 6 inches during the winter. Chopped leaves or wood chips are ideal to use for mulch. Avoid using whole leaves for mulch, as they obstruct water from soaking into the soil. Don't place the mulch too closely to the stem, as it will encourage rodents and stem rot. Mulch is helpful in retaining soil moisture and also protects the shallow roots.
Boxwood is a heavy feeder shrub. Sprinkle a slow-release granular fertilizer onto the soil around the boxwood once a year, preferably in the spring. This will support proper growth and encourage dense foliage. Your shrubs are also less likely to be attacked by infections and diseases if you give them fertilizer regularly. You may want to give your boxwoods growth activators to help them become more resilient. This will support them in developing drought-resistant, insect-resistant and disease-resistant properties.
Pruning your boxwood shrubs will encourage healthy growth and keep them looking attractive. Boxwoods are easily trimmed to whatever shape you desire. If you want to encourage more growth, it's best to trim off the leading growth. This will increase the production of new branches. To encourage growth of more foliage you need to trim a bit of the previous year's branches. Always be vigilant for dead branches or parts that may be at the center. If left to accumulate, they can precipitate fungal infections which will spread to the rest of the shrub.
Boxwood shrubs can tolerate normal winds, but some protection is necessary when the harsh winter winds manifest. The winter sun may also cause sun scalding, which will ruin the appearance of your boxwoods. It's best to erect a screen around the shrubs. You can also cover them with burlap material or evergreen boughs. Make sure you allow them adequate space to enable comfortable breathing and good air circulation.
Photo by: Mykhailo Pavlenko / Shutterstock.
Trimming or shearing encourages new growth and is best done in late spring or summer. Avoid pruning or trimming in fall or winter, because the new growth can be too tender to handle frost. When cutting back, don’t overdo it, as this can produce too much growth. While a nice, compact bush may look healthy on the outside, that dense outer foliage can keep air and light from getting to the inner part of the plant. Dead leaves and stems can also build up and harbor fungal diseases. Thin the outer growth annually so that air and light can get in, and prune away any dead or diseased branches from the center of the plant. Shearing can be done with hand pruners , hedge clippers or electric trimmers .
Help them get through the winter by providing some extra protection from cold temperatures and winds with burlap wraps , decorative protection , or a windbreak. Surrounding them with a good layer of mulch will keep the roots insulated and conserve moisture to prevent dehydration damage from cold winter winds. If bronzing of the foliage does occur, resist the temptation to cut it back immediately. The new growth that is prompted from cutting won’t be any hardier than what was damaged, so hold off until spring when new growth can make a comeback.
Boxwoods are extremely flexible and can adapt to various types of soil — provided it drains well. Ideal soil pH is 6.5 to 7. For more on proper soil preparation and how to adjust your pH if needed, read Garden Soil 101.
Amendments & fertilizer:
Apply a balanced all-purpose fertilizer in spring to promote foliage growth, and again in fall to encourage root growth. Apply the fertilizer throughout the root zone, which extends beyond the crown of the plant. Be careful their shallow root systems can be damaged by over fertilizing.
Newly planted shrubs will need regular watering for the first year, especially during hot, dry weather. In their second year, root systems are still developing, so continue to water regularly if rainfall isn’t enough. Once established, they’re quite drought tolerant and only need extra watering during dry spells. Water at the base of the plant to keep the foliage dry and conserve moisture with a layer of mulch that extends 12 to 15 inches past the foliage line.
Diseases and pests:
Boxwood leaf miners, scale insects, lesion nematodes, caterpillars and mites can be a problem treat with organic neem oil or insecticidal spray . They can also be susceptible to powdery mildew, Pythium root rot, canker and leaf spots. Boxwood blight is a serious problem in many states. See below for more information and planting alternatives.
A useful part of a deer-resistant garden, as the same alkaloid that makes them toxic also makes them distasteful and can give off a pungent scent, deterring deer.
How to Care for Boxwood Beauties
Boxwood Beauty (Carissa macrocarpa “Boxwood Beauty”) is an evergreen shrub that grows up to 2 feet tall. This dwarf Natal plum cultivar has fragrant white flowers, dark green leaves and an irregular, weeping growth habit. It produces 2-inch round fruits that turn red when they ripen in the summer. Unlike other Natal plum plants, this cultivar lacks thorns and is suitable for walkway edgings. Native to Africa, Boxwood Beauty grows in U.S. Department of Agriculture plant hardiness zones 9 through 11, and tolerates temperatures as low as 25 degrees F. It tolerates salt spray and salty soil and is an ideal plant for coastal regions.
Prepare a planting site for your Boxwood Beauty in the spring in full sun or light shade. Test the soil to determine the pH level and add elemental sulfur if the pH is above 6.5 or limestone if the pH is below 5.5. Work compost into heavy clay soil to ensure adequate drainage.
Dig a hole twice as wide and the same depth as the root ball. Space Boxwood Beauties 36 to 60 inches apart. Place the root ball in the center of the hole, fill the hole with soil and gently press the soil around the root ball. Add a 3-inch layer of mulch in a drought-prone area to prevent the soil from drying out.
Add a balanced, general purpose fertilizer when you plant the Boxwood Beauty. Fertilize established plants every spring. Add trace elements to alkaline soil if the soil test indicates low levels of these nutrients.
Provide 1 inch of water every week during the first two years to help Boxwood Beauties to become established. Water established plants when the soil feels dry but before the plant begins to wilt. To prevent root rot, do not allow the soil to become waterlogged.
Prune frequently to control shape and preserve the Boxwood Beauty cultivar characteristics. Without pruning, the shrub will develop an irregular shape and lose its compact growth habit, according to Purdue University Cooperative Extension. Prune back any frost-damaged stems or branches in the spring.
Inspect stems and the undersides of leaves regularly for tiny insect pests, such as spider mites and scale insects. Remove insects by hand or with a forceful stream of water. Check for signs of fungus disease such as stem galls or dieback, and remove and destroy diseased stems and leaves. Young and stressed plants are particularly susceptible to infestations and disease.
Planting boxwood bushes that are less susceptible to the boxwood leafminer is one way to prevent infestations. Slower growing boxwoods such as the English boxwood, Pendula and Suffruticosa are somewhat resistant to this pest. There are natural predatory insects such as green lacewigs and parasitic waps that feed on boxwood leafminer keeping them under control.
- Boxwood bushes infested with boxwood leafminers have water-soaked blisters on the lower portion of the leaves.
- Although boxwood bushes are not usually killed by infestations of the boxwood leafminer, heavy infestations can cause poor color and thin foliage development.