A Gardener’s Intro to the Cornus Kousa

Cornus kousa

If you're looking for a tree that offers four seasons of interest, attracts wildlife, and is easy to fit into your landscape, look no further than the cornus kousa, or Japanese flowering dogwood. With its drifts of white or pink blossoms in the spring, bright red berries in late summer, gorgeous fall foliage, and interesting bark, it's sure to add interest to your garden all year long.

All About Cornus Kousa

Cornus kousa is one of those trees that can easily be at home in any landscape. It's not a huge tree -- growing to a maximum height and spread of 15 to 30 feet, depending on which cultivar you plant. Younger Japanese flowering dogwoods have a vase-shaped growth pattern, but as the plants mature, the branches take on a more horizontal growth pattern, so it has a graceful, spreading canopy.

Cornus Kousa characteristics

Its size, as well as the fact that it doesn't have a very deep root system, means that this is one of the few trees that's safe to plant under power lines or near driveways or pavement because the roots won't damage the concrete. This gives you a lot more flexibility as far as where you can plant this tree.

Cornus kousa also attracts wildlife; specifically, butterflies are attracted to its blooms in spring, and songbirds eat the red fruit it produces in late summer.

Cornus kousa blooms in May and June and is hardy in zones five through eight.

Planting Cornus Kousa

Cornus kousa is best planted in spring rather than fall. Its roots need some time to establish before the ground freezes. Plant after the last frost date in your area and be sure to keep your new tree well-watered as well as mulched. It's important not to let the tree's roots dry out at all as it's getting established.

Light and Soil Requirements

Japanese flowering dogwoods grow best in full sun to partial shade. However, those planted in full sun can sometimes suffer from sun scorch if they're in full, blazing late afternoon sun. A spot with morning sun and afternoon shade is ideal if you have it.

The soil is probably the biggest factor in success in growing healthy, beautiful cornus kousa trees. Cornus kousa needs fertile, loamy, moist, well-drained soil.

  • Ideally, you'll want to really spend some time amending the soil in the area where you plan to plant a kousa dogwood, mixing in plenty of compost and manure before planting, so that the soil is rich and absolutely loaded with organic matter.
  • It's important, though, not to just amend the soil in the planting hole, because that encourages the roots to stay right there. You'll want to mix organic matter into the surrounding area, giving the roots plenty of good, rich soil to grow into.
  • Tilling or double-digging the area before planting would be ideal, and then you would maintain that level of fertility by topdressing with fresh compost every year and using plenty of organic mulch.

How to Grow Cornus Kousa

Once you've provided the cornus kousa with the right light and soil conditions, they're fairly easy trees to maintain. The most important thing to monitor when growing kousa trees is to make sure they're getting the proper amount of water.

Water

Because it doesn't have a massive, deep root system, cornus kousa absolutely does not tolerate drought. You'll need to water deeply and regularly during dry periods. Long, thorough waterings are better than several brief, shallow ones.

Ideally, you'll want to water once per week, to a depth of six inches.

The easiest way to gauge this is to dig down into the soil, and watering until the soil six inches down is moist. In time, you'll know how long it takes to reach that depth, but at first you might have to test it every once in a while to see if you've watered enough.

Mulch

To give your trees a little added drought protection (as well as fertility), mulch around it at least three feet in all directions, applying at least six inches of mulch. Just be sure not to mound it up against the trunk, since this can lead to rot.

Added benefits of mulching include fewer weeds to contend with, and avoiding the risk of damaging the trunk of the tree with the lawn mower or weed trimmer.

Fertilizing

If you've done a soil test, you should follow any guidelines for fertilizing based on those results. If not, use a balanced organic fertilizer, applied in April or May.

Pests and Diseases

Unlike regular flowering dogwoods (Cornus florida), cornus kousa are resistant to anthracnose (which has killed many, many dogwood trees) as well as powdery mildew.

Generally, cornus kousa doesn't have any pest or disease problems. It's even deer resistant, so if you have had issues with deer nibbling on your trees and causing damage, this might be a good plant to try.

Pruning

In late winter or very early spring, you'll want to prune out any branches that are crossing or rubbing against one another, as well as any that detract from the overall shape of the tree.

It's also a good idea to regularly inspect the tree and remove any dead branches as you notice them, just to keep the tree looking tidy.

15 Stunning Cornus Kousa Varieties for Your Garden

Whether you're looking for vibrant fall color, abundant blooms, or interesting variegation, there's likely to be a kousa dogwood cultivar that will suit your garden perfectly. Some need more sun or shade than others, but all need good, fertile soil to thrive.

Autumn Rose

'Autumn Rose' has pink-tinged white flowers, yellow spring foliage, and pink to light red fall foliage, making this a unique, colorful tree from spring through fall.

Beni Fuji

Cornus kousa 'Beni-Fuji'

'Beni Fuji' is a stunning, unique variety of kousa dogwood, with deep red-pink flowers and a naturally-shrubby form. You can either train it into a tree or let it remain more shrub-like in appearance.

Blue Shadow

'Blue Shadow' has bluish-green foliage, white flowers, and strong red fall foliage making this a stunner all year long.

Bon Fire

'Bon Fire' has creamy white flowers that eventually take on a pink tinge. It also has yellow variegated summer foliage which turns reddish-orange in fall.

China Girl

Cornus kousa 'China Girl' fruit

'China Girl' is an early bloomer that produces abundant large white flowers and also has excellent fall color.

Gold Star

Cornus kousa Gold Star

'Gold Star' produces plenty of pretty white flower bracts, but this cultivar is even more beloved for its unique foliage. A broad gold band runs along the center of each dark green leaf, making this a showstopper even when it's not in bloom.

Elizabeth Lustgarten

'Elizabeth Lustgarten' is one of the few weeping cultivars of kousa dogwoods. This low-growing tree produces long, graceful weeping branches loaded with plenty of white flowers.

Little Poncho

Cornus kousa 'Little Poncho'

If you're looking for a dwarf kousa dogwood to grow in beds or even in large containers, 'Little Poncho' might be a good option. It grows to a maximum height of eight to 10 feet tall and has large white flowers.

Madame Butterfly

'Madame Butterfly' produces abundant white flowers. The unique thing about this cultivar is the shape and habit of the flowers, which turn vertical, looking like butterfly wings.

Milky Way

Cornus Kousa Milky Way

When kousa 'Milky Way' blooms, it REALLY blooms -- when in full bloom, the white flowers are so abundant that they can conceal the tree's foliage, making the tree look like a solid mass of white flowers. This is also a bit more hardy than most kousas, hardy to zone four.

Moonbeam

'Moonbeam' produces large (seven to eight inch) flowers that are creamy white with delicate pink at the tip of each bract.

National

Cornus kousa 'National'

'National' has large white flowers in spring, and its foliage turns a deep burgundy color in fall.

Snowboy

Cornus kousa 'Snowboy'

'Snowboy' has green-gray leaves edged in white and white blooms. The foliage color for 'Snowboy' is more showy in the shade; if you plant in a sunnier spot, the variegation will fade.

Summer Stars

'Summer Stars' produces abundant small white flowers and has gorgeous reddish-purple fall foliage.

Wolf Eyes

Cornus Kousa Wolf Eyes

'Wolf Eyes' is a variegated kousa, with mint-green leaves that have bright white variegation and wavy edges. It blooms in white, and has pink to red fall color.

Right Plant, Right Place

Cornus kousa isn't a difficult plant to grow, but it is vital that you provide it with the lighting conditions, rich soil, and adequate moisture that it needs to thrive. You'll be rewarded all year long with its stunning blooms, foliage, and bark.

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A Gardener’s Intro to the Cornus Kousa