Cornus Kousa

From the Missouri Botanical Garden website, read the following about the kousa dogwood. “Cornus kousa, commonly called Kousa dogwood, is a small, deciduous flowering tree or multi-stemmed shrub that typically grows 15-30’ tall, with a vase-shaped habit in the early years but eventually maturing to a more rounded form. Bloom occurs in late spring. The showy parts of the Kousa dogwood “flower” (3-5” across) are the four narrowly pointed petal-like white bracts which surround the center cluster of insignificant, yellowish-green, true flowers. Flowers are followed by berry-like fruits (to 1” diameter) which mature to a pinkish red in summer and persist into fall. Fruits are technically edible, but are usually left for the birds. Oval, pointed leaves (to 4” long) are dark green, but usually turns attractive shades of reddish-purple to scarlet in autumn. Mottled, exfoliating, tan and gray bark on mature trees is attractive in winter.

This matter of fact description does not begin to address the beauty of a kousa dogwood in full and glorious bloom. I doubt I have ever written about them in the 10 years I have been publishing my garden design journal. Primarily as I have never ever seen them so spectacular in flower as they are right now. The kousa dogwood is native to Japan, Korea, China, and Taiwan.  They are rated as hardy and thriving in zone 5 to 8, but my experience suggests they can act a little hostile towards our baking summers, and heavy clay based soil. They seem to favor thin compost rich soil on the acid side that drains in a twinkling of an eye. I do find they perform better than American dogwood (cornus florida) in general.

My theory seems to have some support. This has been the rainiest and coolest spring I can ever remember. We have had many more rainy than dry days. It was 48 degrees this morning, and barely 60 degrees this afternoon. The ground is completely drenched. I make an effort to stay out of the garden, even if it means the foot tall weeds are getting closer to 2 feet tall. The grass is squishy. For the Kousas to put on such a rare show of extravagant bloom says there is definitely something in the air that they like.

The actual flowers are small and insignificant.  All of the show comes from the four stiff bright white bracts that surround the flower. In a stellar year, those thousands of bracts overlap one another to produce a solid sheet of white. Even at maturity, a kousa dogwood is small enough to comfortably place in an urban landscape. Sited with some afternoon shade, a routine source of water and great drainage, all a gardener has to do is wait for that one year when all the stars align for a super bloom.

Should you be one of those people who drives the neighborhood to look at holiday lights, a cruise might be in order.  You can spot them for at least a block away. Out of flower, they have handsome foliage, and even more handsome exfoliating bark when they are older-but the star of the once in a blue moon show are the flowers.

In 2009, a hybrid of Cornus Kousa, and the Pacific coast dogwood, Cornus Nutallii, was introduced from the breeding program at Rutgers University. Again, from the Missouri Botanical Garden website:  the dogwood “Venus”  These four trees planted in the tree lawn at my house are young, but they will grow. Even at a 2″ caliper size, I can spot the flowers from several blocks away.

This hybrid is hardier than either parent.  They thrive in full sun, and grow fast when they are happy. The flowers can easily reach 6″ to 7″ in diameter. We have probably planted better than 100 of them since 2011, with only a few losses. They are a little shy to bloom until they have been in the ground for a year or two, but once they start, they are stop you dead in your tracks gorgeous.

They rival the magnolias for the showiest spring flowering tree.  As with Cornus Kousa, Venus flowers in June, avoiding late spring frosts that so often damage the flowers of magnolias.

A pair of small trees I planted 3 years ago are covered with flowers this year.
This shade garden planted some 4 years ago for my clients features a pair of Venus dogwoods. They are especially happy to have them this year.

Comments

  1. nancy debrowski says

    I have a kousa dogwood that is about 4 feet tall. When I got it 2 years ago, it was barely 12″ high. I knew we would be moving & I wanted to take it with me, so I put it in a 12″ pot. Last year it grew very nicely, lots of branching & healthy leaves. After this winter, there were buds on all the ends, but they never opened up. i pruned them & it was very bright green inside…looking very healthy. I thought that might force it to grow leaves, but again, it closed up & hasn’t opened at all. If i trim back a bit more, I can STILL see it is VERY healthy looking, bright green on the inside. My dear aunt gave this to me shortly before she passed away and I desperately want to save it if possible. She was a Master Gardener who trained in England. She is sorely missed by me & all her past clients who loved her work so much. Please tell me what I can do for my kousa dogwood to restore her memory. Thank you. (I took a few pictures if you want to see them, but I don’t know how to attach them here).

    • Deborah Silver says

      Dear Nancy, my take is that your are worrying this tree too much. So much moving, potting, and pruning. Plant the tree in the ground in a spot a Kousa dogwood would like, keep it watered, and leave it alone. Let nature take the lead. Your memory of her will be intact, whether this tree lives or not. But give the tree what it wants, and stand back. Nature will take care of the rest. best regards, Deborah

  2. Eat the berries.
    We take them and squeeze the fruit out of the shell (a lot of work). Great as a chicken sauce or on vanilla ice cream.
    Freezes well.

    • Deborah Silver says

      Dear William, sounds divine. Everything that is divine takes a lot of work, yes? best, Deborah

  3. SandiI Hill says

    Loved your writing on this beautiful specimen. Would love to have one. Where could I purchase one?

  4. Suzanne Gartz says

    I have a 2 year pink Kousa that I thought I was losing because of all the rain we have had. The one peculiar thing is that all the flowers are in the inside of the tree, rather than outward on the limbs. What might be the reason? Live on SW side of MI.

    • Deborah Silver says

      Dear Suzanne, I have never seen that. Maybe a blast of super cold air this spring frosted off the outside buds. best, Deborah

    • Dana Lavelle says

      I too live in SW MI and I have a 4 year old pink Kousa — and the flowers are on the inside. I think that it has only bloomed one other time. It just bloomed and the flowers lasted forever — although small in number.

  5. Barbara LeTarte says

    There’s a splendid, old, Kousa on the east side of S. Hill Rd between Rose Hill and Maple in Milford. It’s on the side of an old house. I used to drive by on that wretched road just to look at the tree!

    • Deborah Silver says

      Dear Barbara, dang, now I have to go to Milford. Thanks for the heads up. I hope I get there in time. all the best, Deborah

  6. I have two Kousa dogwoods. They have been planted for 20 years in my yard northeast of Atlanta. This year was the best show they have ever provided. We, too, had cool wet conditions this spring and they bloomed gloriously. The blooms also lasted longer than usual, but after two hot days the trees were void of blooms. It was sad to see the show end, but it was spectacular while it lasted!

    • Deborah Silver says

      Dear Mary, I agree with you. The Kousa dogwoods, in a good year, are the best of the flowering trees. best regards, Deborah

  7. Nanette Brawer says

    This year, here in New York, the Cornus Kousa are spectacular, as well. I have a sliver of property and am searching for a spot to place one. One large old maple in my front yard has very tenacious air roots that quickly find new sources of soil…so i’m not sure the dogwood would have too much competition to thrive. Oh, what’s a gardener to do? Have a wonderful spring!

  8. I have several stunning varieties of Kousa including Wolf Eyes, Satomi, Lustgarten Weeping, Summer Gold, and my most gorgeous of all Snowboy. Once you get them going they are easy and dependable while my C. Florida have good years and bad years.

    • Deborah Silver says

      Dear Toni, it sounds like you are a fan. I will have to look up the cultivars of cornus kousa that you grow. I am not familiar with Snowboy, among others. As for Cornus Florida, some years are better than others for me. I could take it or leave it. But a kousa is very hard to pass up. best regards, Deborah

  9. Jeff Schmones says

    I have a kousa that I planted 3 years ago. I have only 1 flower. The leaves are curling slightly. Any suggestions.

    • Deborah Silver says

      Dear Jeff, take a few pictures, and go to your local nursery for an assessment.If you don’t get good help there, look for a certified arborist who could come and take a look. I hope you have better kousa days ahead. Best, Deborah

  10. Sagar Sinhar says

    I am resident of Charlotte,NC and I planted two of these this season. Do we need to provide any fertilizer for them to grow well?

    • Deborah Silver says

      Dear Sagar, I do not have any kousa dogwoods in my yard, so I cannot advise you. Visit a local nursery, and ask for some advice on their culture. My old American dogwoods-I do nothing to them except water a lot from the late summer in to the fall. But my regimen may not help you. Seek advice from a knowledgeable tree person near you. best, Deborah

  11. Susie's Gardens says

    The Kousa Dogwoods are stunning this season!

  12. From a distance, they always look like a flock of small white doves decided to festoon one tree. Spectacular!

  13. Dear Deborah,
    I love your blog and am finally posting to thank you for the regular gift in my inbox. I understand your enthusiasm but I think I’m with Mike above, as I prefer the form of C. florida. Speaking of trees, one of my favorites is Oxydendrum arboreum. These have beautiful form as well and magnificent fall color. I occupy myself every fall in tracking all the different leaf colors they exhibit.

    • Deborah Silver says

      Dear Melissa, it is a good thing that we have choices, and the freedom to plant what we like. Oxydendrum is indeed beautiful, but it marginal at best in my zone. Which means as soon as it would get big and gorgeous one of our terrible winters would take it. all the best, Deborah

      • Dear Deborah,
        I’ll try to keep in mind our climate’s ability to support those while I’m trying to work outside on rock-hard ground in relentless 95 degree heat. You may have the better deal. Best, M

        • Deborah Silver says

          Dear Melissa, I always think gardeners in other places have a better deal than I do. The proverbial grass is greener on the other side. It is probably closer to the truth that no matter where you garden, there is the occasional wish to be gardening somewhere else. And that every gardener has troubles, no matter where they garden. best, Deborah

  14. I have 2 Kousa in the front of our house. They have been there approximately 7 years and have put out a show of blooms each and every year. They seem to be very happy with the light/water they are currently receiving. I am curious about the need for pruning them…. is that something I should be doing and if so, when? Mine are quite full and almost bush-looking. I noticed in some of the photos in your post you can see more detail of the inside branches. I am thinking I should possibly thin them a bit – or I should say have someone come out who knows what they are doing thin them! I enjoy your posts!

    • Deborah Silver says

      Dear Dennie, I have always been very cautious about pruning dogwoods of any type. I don’t think they take to it so well. I do think they naturally thin out as they age. best, Deborah

  15. Christina says

    I live in Princeton, New Jersey, a town in which Kousa dogwoods are plentiful, though I didn’t realize how plentiful until this spring. Nearly every home built during the 1950s, 60s and 70s seems to have at least one, and more likely two, planted somewhere on the property. Between those and the University and Seminary campuses, the town was a memorable sight for well over a month this year. Between the unusually cool temperatures and abundant rain here as well, their flowering seemed to last far longer than usual. While the town’s many cherry and crabapple trees are often a topic of discussion here, this year it was the Kousa dogwoods. I recently read that they are considered “invasive” in some locales from the standpoint of being overplanted in American suburbs and by institutions with extensive grounds. Hard to fathom such beautiful trees as invasive in any sense of the word.

    • Deborah Silver says

      Dear Christina, I think they are gorgeous-I hardly consider them invasive…unless invasive means popular. best, Deborah

  16. Hi deborah! I was just researching a good breed of dogwood for my yard. This post is simply perfect timing. Thank you Amy Dolan

  17. Pippa Honess says

    We planted a Cornus Kousa ‘China Girl’ here in our garden in West Sussex UK after seeing and admiring the one my daughter has in her garden in upstate New York. It was about 6’ when we planted it 2 years ago and this year it has come into its own with a wonderful display. I’m just hoping that this year the squirrels and birds will let us keep some of the fruit! We haven’t seen Venus in this country.

  18. Gerald Salerno says

    I agree. My Kousas have never looked so stunning. I had given up on the American Dogwood as mine have always seem to struggle, but the Kousas always look good. Water is the key with these guys and this year we’ve had plenty of that. Unfortunately the abundance of rain did cause the death of several of my perennials due to root rot.

  19. Susan Brooks says

    Our Kousa is about 25 years old and is the queen of our shade garden. In the past 5 years we have had the surprise gift of many volunteer Kousas, which we’ve shared with friends. It’s a lovely hardy tree in SW Michigan. It’s in shade most of the day and our soul is acidic, enriched with yearly applications of compost.

  20. Brenda Marean says

    I live on the North Shore of MA . My Kousa at age 15 is amazing. In fact this has been a spectacular year for 3 tulip trees and roses! I guess their abundance of blossoms is pay back for a cold wet spring!

  21. Joyce Baker says

    Thank you for introducing those of us in Zones not favorable to such beautiful plants, shrubs and trees as this and others that have been in your newsletters. A shame that Zones make such a difference in what one can have in their garden. A difference of a couple states makes such a difference. This dogwood seems to need a lot of space to best show its beauty.

    • Deborah Silver says

      Dear Joyce, the biggest ones I have seen are 18-20′ tall, and as wide. I understand about zone restrictions. I wish I could grow roses like they do in California. But that is a very old tree. best regards, Deborah

  22. Matt Brand says

    I have mixed feelings about Kousa. They seem overused (for good reason), and are almost ‘too’ showy for my taste. I would rather see more people planting native Cornus Florida and admiring the relatively shorter display of white, and the elegant branching and foliage that is on display once the flowering is done.

    • Deborah Silver says

      Dear Matt, I have mixed feelings about American dogwoods. I have 4. 2 are in a state of decline from who knows what. Probably they simply do not like where they are planted. The other two bloom every other year, but always have significant branch dieback. The leaves are afflicted with leaf curl all summer long. I estimate that all 4 are between 25-35 years old. Some years I think spring flowering trees are silly, and other years I am enchanted. There is good and bad with everything in the garden. The Kousa dogwoods are just particularly beautiful this year. best, Deborah

  23. I had one which I nurtured from a whip. It bloomed exponentially one or twice but was commonly reserved in nature. I loved the foliage as well. This Winter was particularly brutal this year in Montreal with a thick snow cover. The plethora of Rabbits that call the local empty lots took to eating anything everything they could including the outer bark on my beloved Cornus Kousa. This resulted in the plant being girdled and is for all intents and purposes dead.

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