When to trim laurels?

Mountain Laurel Trimming Tips: How To Prune Mountain Laurel Bushes

Mountain laurel, or Kalmia latifolia, is an evergreen shrub in U.S. hardiness zones 6-8. It is beloved for its unique, open branching habit; large, azalea-like foliage; and its beautiful, wax-like star-shaped flowers which are available in red, pink or white. Growing to a general height and width of five to eight feet (1.5 to 2 m.), cutting back mountain laurels may occasionally be necessary to fit the space they are in. To learn how to prune mountain laurel shrubs, keep reading.

Mountain Laurel Trimming

Aside from being a beautiful flowering evergreen, mountain laurel is also very popular for being low maintenance. Generally, mountain laurel plants require little pruning. However, as with any plant, it is sometimes necessary to prune dead, damaged, crossing branches or water sprouts from mountain laurel plants.

While mountain laurel plants tend to have an open, airy growth habit, it may also be necessary to prune out some inner branches to promote

good air circulation throughout the plant, and also allow more sunlight in to the center of the plant.

Mountain laurel plants bloom in spring. After this bloom period, most experts recommend cutting off the spent flowers to promote an even better bloom display the following year. Mountain laurel pruning should also be done at this time, right after the plant flowers. However, emergency pruning, such as trimming out diseased or storm damaged branches, can be done anytime.

How to Prune Mountain Laurel Bushes

When pruning a mountain laurel, it is always important to used sharp, clean tools. You may require hand pruners, loppers, a pruning saw or a bow saw, depending on the thickness of the branches you are trimming. Always make clean, smooth cuts, as jagged cuts can heal over slower, leaving the branch end open and susceptible to pests or disease.

It is also important to note that if you are trimming out diseased branches, you should dip your tools in a sanitizer such as bleach or rubbing alcohol between each cut to prevent the further spread of the disease.

When cutting back mountain laurel, older, tired branches can actually be rejuvenated by cutting them all the way back to the ground. Mountain laurel plants are very forgiving about hard pruning. However, a general rule of thumb when pruning trees and shrubs, is to never remove more than 1/3 of the plant in one pruning.

First, prune out large branches that need rejuvenation. Next, remove dead, damaged or crossing branches. Then remove any water sprouts or branches that hinder air flow or light exposure. After pruning, it is a good idea to give mountain laurels a little boost with a fertilizer for acid-loving plants.

Mountain laurel, Kalmia latifolia: “Calico Bush”

The first time I remember seeing mountain laurel blooming in the wild was in a most unlikely habitat, the parking lot of Mount Vernon, George Washington’s historic estate in Virginia high above the Potomac River. In contrast to the formal, meticulously manicured flower and vegetable gardens inside the historic site, the shrubs bordering the asphalt were a ragtag bunch. The mountain laurel was growing on the edge of a scruffy little woods among some other weedy residents. I was able to identify it by its clusters of very distinctive, small, cup-shaped polygon flowers. The plants were clearly left to grow on their own and the mountain laurel was rather leggy with sparse leaves. However, even in such challenging circumstances, these plants in bloom were eye-catching and appealing.

Is mountain laurel the right shrub for your garden? Read on.

Above: Mountain laurel on a hillside beneath oak and beech trees in late autumn. Photograph by Ery Largay, courtesy of Nature Serve.

That Kalmia latifolia, which is a native evergreen plant, should be growing on the grounds of an American historic site is totally appropriate since its presence in the colonies was first recorded as early as 1624. It is the state flower of both Connecticut and Pennsylvania and is a member of a small genus (only seven species) in the Ericaceae family. That makes mountain laurel a relative of other woody shrubs such as blueberries and cranberries as well as rhododendrons and azaleas, with which it is often combined in woodland gardens.

Mountain laurel is found in the eastern United States from New England south to Louisiana and the Florida panhandle, where it is found in forest margins, mountain slopes, and cool meadows. In spring it can be seen in bloom along the Blue Ridge Parkway in North Carolina and in the pitch pine forests of upstate New York where it grows abundantly. It is also well suited to the coastal Pacific Northwest, thriving in the cool, moist climate.

Above: Photograph by Dan4th Nicholas via Flickr.

Cheat Sheet

  • If visitors to your garden include pets or children, be advised that all parts of Kalmia latifolia are poisonous if ingested.
  • This plant attracts hummingbirds, butterflies, and bees (although their honey will be toxic and should be avoided).
  • Protect the delicate fibrous mountain laurel roots with a two-to-six-inch layer of mulch.
  • This plant cannot tolerate salt so avoid placing it near the ocean or close to roads in cold climates where salt is used to melt snow and ice.

Keep It Alive

  • Plant mountain laurel in well-drained, cool, moist, acidic soil in USDA zones 5-9.
  • Good drainage is essential to avoid rot. If drainage is an issue in your garden, consider planting this shrub in a raised bed.
  • Mountain laurel will grow in deep shade to full sun but is happiest in moderate to partial shade. In full shade it will produce fewer flowers while too-bright sun can cause scorching of the leaves.
  • Deadheading spent blooms will increase the next year’s flower production.

While mountain laurel can exceed 30 feet in the wild, in cultivation it rarely grows taller than 10 feet and seldom requires pruning. However, if your plant is outgrowing its spot in your garden, you can prune it just after flowering down almost to ground level. Kalmia latifolia is a slow grower but tolerates hard pruning very well and will grow again into a large shrub in several years time.

Above: Photograph by Stephen Horvath via Flickr.

The nickname “calico bush” alludes to the tiny dots and lines on mountain laurel flowers, which are said to resemble the prints on calico fabric. In addition to their distinctive appearance, the flowers have an unusual way of dispensing pollen. The stamens are arched, their tips held under pressure by the rim at the top of the flower petals. When a bee or other pollinator lands on the flower, the weight of the insect releases the stamen, which flings its load of pollen up like a tiny catapult.

Above: K. latifolia ‘Minuet’. Photography by Peter Stevens via Flickr.

While the flowers, which bloom in late spring, are its most distinctive feature, mountain laurel stays green all year and provides uninterrupted interest with prominent buds that precede the flowers and brown seedpods which appear in late summer and remain on the plant throughout the winter. In addition, as the plant ages, its branches can become gnarly with attractive peeling bark. The flower colors of native mountain laurel species are mainly limited to pink and white but in recent years many hybrids have appeared, widening the color choices.

Above: K. latifolia ‘Peppermint’. Photograph via Broken Arrow Nursery.

Most prominent among hybridizers is Richard A. Jaynes the founder of the Broken Arrow Nursery in Hamden, Connecticut. On the nursery’s website are listed 21 varieties of Kalmia latifolia that are all the company’s own introductions. They include “Firecracker,” a small plant with bright red buds that mature into white flowers; “Minuet” which has deep maroon flowers with white markings; and “Peppermint” with pale pink flowers striped in deep red. Jaynes is also the author of an exhaustive volume Kalmia: Mountain Laurel and Related Species, required reading for the true mountain laurel connoisseur.

Get ideas on how to plant, grow, and care for more of our favorite shrubs and hedges with our Shrubs: A Field Guide. To see how mature shrubs will look in your garden, read:

  • Landscape Ideas: Blazing Color with Red Twig Dogwood, 5 Ways
  • Azaleas 101: A Field Guide to Planting, Care & Design
  • 10 Garden Ideas to Steal from Instagrammers
  • Winter Enchantment: 9 Best Witch Hazels for a Luminous Garden
  • 10 Best Garden Design Ideas for 2018

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Thursday – November 12, 2009

From: Universal City, TX
Region: Southwest
Topic: Pruning, Shrubs
Title: Pruning Texas Mountain Laurel
Answered by: Janice Kvale

QUESTION:

How much can I prune a 10 year old mountain laurel to re-shape it and when?

ANSWER:

Sophora secundiflora (Texas mountain-laurel) is a wonderful evergreen shrub which breaks forth in February and March with showy purple blossoms whimsically smelling like grape bubblegum or perhaps Koolaid. But you know all that so let’s get to the crux of the question. This is not a shrub that usually requires pruning, so is there a good reason to prune your specimen? Let’s assume there is and you want to do something about it. Those blossoms appear only on year-old wood, so you may not want to prune until after the bloom period. If you prune after blossoming to preserve the bloom for next year, you may find pruning stimulates increased blossoming. The classic rule on pruning is prune during dormancy and, in Texas, during the winter (you may lose the blossoms for the next season) or during the hot summer.

First, envision how you want the finished product to appear. Mountain-laurels may be shaped into bushy shrubs or taller trees. The U. S. Department of Agriculture Forest Service describes Sophora secundiflora (Texas mountain-laurel) as averaging between 15-25 feet tall with the potential of reaching 50 feet high! On the other hand, the bushier they are the better screens they make. For a tree-like appearance, encourage height by pruning out the lower branches leaving between one and three trunks. With this choice, there is increased maintenance in keeping the suckers at bay. For a shorter, bushier appearance, trim the upper branches to discourage height. Because this shrub is slow growing, it may take time (think years) to achieve the look you are striving for. Unless you want faster growth (which may require more need to prune), do not fertilize the shrub or the grass around it.

Prune no more than one third of the shrub at a time, taking first any dead, broken or diseased parts. Then take out the thin, spindly branches with narrow crotches.Cut the branches back to the point of origen or next lateral branch. Pruning paint is not necessary as there are few or no diseases to cause concern. For general pruning principles, read our How To article on pruning. Also, you can always hire a landscape professional to advise you on shaping the shrub and doing the pruning. Our Suppliers list may help in finding such a person.

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The mountain laurel (Kalmia latifolia) is a medium-sized evergreen bush also known as calico bush or ivybush. It is a beautiful native American shrub with glossy leaves and small, star-shaped white and pink flowers. The flowers grow in attractive, eye-catching clusters in mid to late spring.

Mountain laurel is hardy in U.S. Department of Agriculture Hardiness zones 5 through 9. It’s average size is 8 feet tall and wide. It is a lovely bush for the outskirts of a woodland garden or as a foundation plant. It is beautiful enough to have earned the State Flower title for the state of Connecticut. Consider using the mountain laurel in place of the later blooming rhododendron. The shape, appearance, and needs of the two shrubs are very similar.

How to Grow and Care for Mountain Laurel

Mountain laurel is easy to grow from transplants. While many plants that you might run across in the wild will not transplant well, young mountain laurels are highly adaptable. Most of us will probably not find one in the wild though, so we’ll have to hunt for our mountain laurel at our local nurseries. Mountain laurel tends to sell out early in the season, so plan ahead and beat the crowd. Select a variety that will work well in your region.

Mountain laurel is a sun-loving plant. It will especially appreciate several hours of morning sun and a partially sunny afternoon. If you can plant your shrub where this preference can be met, you will be rewarded with bountiful blossoms.

Once you have selected a sunny site to plant your mountain laurel in, treat it to acidic, well-drained soil. To add acid to your soil before planting, mix peat moss into your soil. Every spring before your mountain laurel blooms, add an acidic fertilizer into the soil in the form of peat moss, compost, or acidic mulches, like shredded bark or pine needles. The mulch will serve dual purposes: it will nourish your plant with the acid it loves and it will maintain soil moisture.

Mountain laurel needs to be watered regularly. The soil can feel moist to the touch at all times, but it will be happy if left a bit dry, too. It would rather be dry than waterlogged.

While pruning isn’t a must do, you can prune your mountain laurel to maintain its shape and to encourage flowering for the next season. Timing is everything when pruning this bush, so prune as the flower buds begin to fade away. If the buds are starting to drop themselves, it is too late to prune. You don’t want to make the mistake of pruning off the growth buds for next year.

Pests and Problems

Mountain laurel is susceptible to the lacebug. This nasty little pest sucks the moisture out of the leaves. The leaves will appear spotted and whitish. Unfortunately, the only way to get rid of a lacebug infection is to treat it with a pesticide. Treat the underside of each leaf if you notice your shrub has succumbed to this pest.

Another problem for mountain laurel is leaf spot. This fungal disease can often be prevented by purchasing a resistant variety and by providing plenty of sunshine and air circulation to your shrub. Prune your branches if that will help it breathe easier. Clean dead leaves away from the base of your mountain laurel, too. This can help to further prevent the spread of leaf spot to other leaves.

Mountain laurel is highly toxic to people and pets when ingested, so keep this in mind as you consider whether or not this shrub is right for you.

Varieties to Consider

  • ‘Elf’ is a semi-dwarf variety with miniature leaf size. The blooms are nearly full size, which gives the shrub a whimsical appearance when in bloom.
  • ‘Pinwheel’ has a compact form with hardy leaf structure that is resistant to leaf spot. The name is derived from the flowers which have scalloped edges. The center of the flower is white, and the tips are a deep red color which creates a striking contrast.

Common Questions and Answers About Mountain Laurel

by Erin Marissa Russell

Can you grow mountain laurel from cuttings?

Take cuttings to propagate mountain laurel from the current year’s growth between August and December. Treat the bottom of the stem where you took the cutting with rooting hormone and plant in a container filled with a mix of equal parts perlite, coarse sand, and peat moss. Water deeply and mist the leaves of the cutting after planting, then cover with a plastic bag propped over the container. Remove the plastic bag only to water and mist the cuttings each day. Keep soil moist, and find a spot that’s out of direct sunlight. Cuttings can take four to six months to develop roots.

Can you prune mountain laurel?

While only minimal pruning is needed for mountain laurel, you will occasionally need to prune back dead, damaged, or crossing branches, or you may need to create space for air to circulate and sunlight to reach the interior of the laurel’s branches. Cut the faded flowers off after the first bloom in spring to encourage your mountain laurel to bloom again. Perform maintenance pruning as well, though pruning to remove damaged branches can be done at any time. Use clean, sterilized gardening tools to prune your mountain laurel, sanitizing the tool between cuts if you’re removing diseased areas. Remove large, old branches that need refreshing as well as damaged, crossing, or diseased branches. Never remove more than one third of the plant at a time.

Can you transplant mountain laurel?

Transplant mountain laurel in the fall, between late August and late October. When you’re digging up the plants, remove as much of the root ball as you can get. Be careful to keep the soil clinging to the roots as much as possible. Water your mountain laurel plants well for a year after transplanting, and add a layer of mulch such as pine needles or shredded hardwood on top of the root zone.

Do mountain laurels bloom every year?

Mountain laurels bloom yearly in mid to late spring, displaying flowers in shades of pink to white.

How big do mountain laurels get?

When cared for properly, mountain laurels can reach heights between six and 20 feet.

How do you propagate mountain laurel?

Propagate new plants from your established mountain laurel by making a cutting between August and December from the current year’s growth. Treat the bottom end of the cutting with rooting hormone, and plant in a container filled with a mix of equal parts perlite, coarse sand, and peat moss. Water the cutting deeply after planting and mist its leaves, then place an upside-down plastic bag over the top of the container to keep soil moist. Only remove the plastic bag to water or mist the plant each day. Keep the soil moist while the cutting grows, and find a location for the container that is out of direct sunlight. Cuttings will develop roots in four to six months.

Should I deadhead mountain laurel?

You can deadhead mountain laurel by cutting back the foliage with faded blooms after the first bloom of the season has expired. Deadheading will encourage the mountain laurel to bloom again.

Will mountain laurel grow in full sun?

Mountain laurel prefers to grow in locations that get dappled sunlight, but the plants can tolerate either full sun or partial shade. Avoid spots that get full sun and reflect light and heat from southern-facing or southwestern walls. In especially hot climates, partial shade is best for mountain laurel.

Want to learn more about Mountain Laurel?

TRIB Live covers Mountain Laurel a Delicate Shrub

Bay Weekly covers Give Rhododendrons and Mountain Laurel a Head Start

doityourself covers 3 Tips for Pruning Mountain Laurel

Gardening Know How covers Growing Mountain Laurel

Gardening Know How covers Mountain Laurel Losing Leaves

Gardening Know How covers Pruning Mountain Laurel Bushes

Gardening Know How covers Rooting Mountain Laurel Cuttings

SFGate Homeguides covers Mountain Laurel Not Blooming

Hunker covers How to Propagate Laurel Cuttings

Hunker covers When Does Mountain Laurel Bloom

Plant Answers covers Mountain Laurel

the Spruce covers Mountain Laurel Growing Tips

Kalmia Latifolia – University of Connecticut

Mountain Laurel (video) – Land Designs Unlimited

How should I prune my Texas mountain laurel?

  • Texas mountain laurel Texas mountain laurel Photo: Treesearch Farms

Photo: Treesearch Farms Image 1 of / 1

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Image 1 of 1 Texas mountain laurel Texas mountain laurel Photo: Treesearch Farms How should I prune my Texas mountain laurel? 1 / 1 Back to Gallery

From: Universal City

Question: How much can I prune a 10-year-old mountain laurel to re-shape it and when?

Answer:

Sophora secundiflora (Texas mountain laurel) is a wonderful evergreen shrub which breaks forth in February and March with showy purple blossoms whimsically smelling like grape bubblegum or perhaps Koolaid.

But you know all that so let’s get to the crux of the question. This is not a shrub that usually requires pruning, so is there a good reason to prune your specimen?

Let’s assume there is and you want to do something about it. Those blossoms appear only on year-old wood, so you may not want to prune until after the bloom period. If you prune after blossoming to preserve the bloom for next year, you may find pruning stimulates increased blossoming.

The classic rule on pruning is prune during dormancy and, in Texas, during the winter (you may lose the blossoms for the next season) or during the hot summer.

First, envision how you want the finished product to appear. Mountain laurels may be shaped into bushy shrubs or taller trees.

The U. S. Department of Agriculture Forest Service describes Sophora secundiflora (Texas mountain-laurel) as averaging between 15-25 feet tall with the potential of reaching 50 feet high! On the other hand, the bushier they are the better screens they make.

For a tree-like appearance, encourage height by pruning out the lower branches leaving between one and three trunks. With this choice, there is increased maintenance in keeping the suckers at bay.

For a shorter, bushier appearance, trim the upper branches to discourage height. Because this shrub is slow growing, it may take time (think years) to achieve the look you are striving for. Unless you want faster growth (which may require more need to prune), do not fertilize the shrub or the grass around it.

Prune no more than one third of the shrub at a time, taking first any dead, broken or diseased parts. Then take out the thin, spindly branches with narrow crotches. Cut the branches back to the point of origin or next lateral branch. Pruning paint is not necessary as there are few or no diseases to cause concern.

For general pruning principles, read our How-To article on pruning. Also, you can always hire a landscape professional to advise you on shaping the shrub and doing the pruning. Our Suppliers list may help in finding such a person.

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