You’ll often read that the kousa dogwood (Cornus kousa), known for its stunning spring/summer blossoms, is ‘a great choice for a small yard’, as it’s smaller than many other deciduous ornamental trees. But I find this advice isn’t universally applicable – a little more research is required if you want a tree that’s right for your property.
As arborists like to say, ‘the right tree for the right place’.
On average, kousa dogwoods grow at a slow-to-medium rate of 1-2 feet per year and reach a height of 20-30 feet (6-9m) tall. Initially of an upright habit, they spread out in maturity to a full width of 16-30 feet (5-9m). In the right conditions they may live for more than 100 years.
This answer comes from own experience as a dogwood enthusiast, and from cross-referencing many other additional sources, including expert gardeners that I’ve consulted and my many tree textbooks.
In terms of mature height, I’ve found a range from 13 feet (4m) at a minimum to 39 feet (12m) at maximum. Quite a range!
For mature spread, I’ve seen and heard ranges from 13 feet (4m) minimum to 30 feet (9m) maximum.
However, the tallest one on record that I know of it is Virginia. It’s 47 feet (14m) tall and has a spread of 49 feet (15m). This is obviously somewhat of an outlier.
To put this in terms that are more easily visualized:
A fully-grown kousa dogwood tree will usually be 1-3 stories tall, and the width of of 2-3 driveways. But they’ve been known to grow twice the height of a 2-story house, and just as wide.
By the way – the kousa dogwood is sometimes referred to as the Chinese, the Korean, the Japanese or the strawberry dogwood!
How long does it take a kousa dogwood to mature?
The term ‘mature’ usually means mature in the reproductive sense, i.e. start producing flowers and fruit. This takes up to 8 years in a kousa dogwood that’s grown from seed, but will usually only take 2 or 3 years in one that’s been propagated asexually, for example by grafting (for more detail on when kousa dogwoods bloom (and when they don’t) check out my post here.
However, most people think of a mature tree as one that looks well established, growing in its natural habit without the support of stakes and the like.
After planting, you’ll usually have a tree stake in place for 6 months to 2 years, depending on lots of factors (see my post here on how to know when to remove tree stakes). In my opinion, a kousa dogwood tree grows into its surroundings and looks good after 5-10 years.
Over 10 years, these trees will usually grow by 10-20 feet and will start to adopt a more spreading habit, initially having more of a vase-like or upright shape.
It’s important to keep the spread in mind, particularly if you’re planting near a driveway or path. The kousa dogwood’s fruit can be fairly messy (not to mention that it’ll attract a lot of birds as well), and the branches will eventually overhang it.
Will a kousa dogwood keep growing forever, or stop at a certain height?
An interesting question. If kousa dogwoods reach a certain height, what happens then? Do they just stop growing?
In practical terms, what happens is that the growth slows down significantly. The trunk increases in girth as do the main limbs, and it perhaps only grows by a few inches a year. Essentially, there are different types of growth – a tree that isn’t growing at all in some sense is dead.
As long as conditions are good for the tree, it may well outlive you – so you need to plan for this tree to get to its maximum size.
Can trees live forever, or do they die of old age? Check out my post answering this here.
What’s the best place to plant a kousa dogwood?
There are a few considerations here:
- In full sun, or partial shade (it differs here from the flowering dogwood, Cornus florida, which dislikes full sun)
- In well-drained, fertile soil – ideally of a slightly acidic pH
- In a place that it won’t outgrow
Even small trees can end up too small for their space. This ‘small tree’ can grow to a height of 3 stories and a similar width.
Ideally then, a kousa dogwood tree should be planted at least 15 feet away from driveways or paths unless you’re hoping for some shade over in these areas.
Do kousa dogwoods have invasive roots?
Kousa dogwoods have shallow roots. The majority grow in the top 18 inches of soil. However, they are not known for being invasive or causing damage to driveways, foundations or plumbing.
As a general rule, plant trees including kousa dogwood at least 15 feet away from foundations. This minimizes the risk of damage and ensures that the roots have ample room to spread out, which helps the tree to thrive.
Are kousa dogwoods hard to grow?
Kousa dogwoods are not hard to grow! Particularly as they’re tolerant to a range of soil types (as long as it’s well-drained. As the roots are shallow, it’s important that it gets some irrigation in the summer when it’s young. They don’t usually need much in the way of fertilizer.
Best of all, they’re naturally much more disease-resistant than the flowering dogwood Cornus florida, which is its nearest cousin. In particular, you’re far less likely to be troubled by anthracnose infections (caused by the ominous-sounding fungus Discula destructiva), which has devastated many flowering dogwoods, particularly in the south-eastern United States. For more detail on this, see my article here.
If a kousa dogwood gets anthracnose, you’re likely only to get some leaf spotting and it won’t affect overall growth and appearance very much.
Do they need a lot of pruning?
Kousa dogwoods do not need a lot of pruning. While they tolerate pruning well, most dogwood-growers think the tree’s best left to its own devices, as it naturally forms an attractive symmetrical framework.
Apart from removing any dead or dying branches (as with any tree, just prune these off straight away) you may wish to do some light pruning to maintain a certain tree shape, or to remove lower branches which can get in the way of a lawnmower. The best time of year to prune dogwood is usually said to be during dormancy in early winter.
The caveat though is that you may limit flowering the next year, so you might need to consider a different strategy for kousa dogwood if you love the blossoms (and who doesn’t). See this post for more specific information.
Can kousa dogwoods be kept small?
Arborists dislike this question, because it’s not straightforward!
In general, kousa dogwoods can be kept small by regular pruning, but what you’ll most often see is people butchering trees by topping them (sawing the tops straight off) every couple of years. This merely encourages lots of shoots to grow from the tops of the trees, which requires more and more work to limit and which really distorts and ruins the look of the tree.
It’s possible to do selective limb-pruning on a yearly basis, but it’s not easy to do this yourself on a long-term basis. You may want to consider consulting a trained arborist on whether this is feasible.
Keep in mind that pruning any dogwood tree will usually limit the flowering (unless it’s done just after flowering) – and the beautiful blossoms are the whole point!
If it’s not too late, consider searching for a smaller cultivar of kousa dogwood. There are even a couple of dwarf cultivars, my favorite being one called ‘Little Poncho’, which only grows 8-10 feet wide and tall.
My favorite smaller kousa dogwood cultivar is the popular ‘Miss Satomi’, which is often more shrub-like in its habit. It usually grows to a maximum height and spread of about 15 feet, but the best thing about it is a stunning show of pink blossoms that lasts well into early summer.
What affects the growth rate?
Kousa dogwood’s known for being more winter hardy than the US-native flowering dogwood. It’ll survive in colder areas of the US, UK, Australia and much of Europe – where there’s an ‘average annual minimum winter temperature’ of down to around -20 °F (-28.9 °C). This corresponds to around USDA hardiness zone 5 – many people think it’ll also do OK in zone 4.
However, the growth rate may be limited in the coldest regions, as frosts in springtime can kill off and nip some of the delicate new growth.
In the warmest parts of the US (hardiness zone 9 and above), the kousa dogwood may struggle to grow well. The flowering dogwood does better in these regions.
The kousa dogwood doesn’t like waterlogged soil. If the soil is marshy, it’ll probably never grow particularly well, and won’t look very healthy either.
Practically, although these factors may limit growth, it’s quite impossible to know exactly by how much they will do so.
Some FAQs about owning kousa dogwood!
Are kousa dogwood deer resistant?
Kousa dogwood are seldom browsed by deer, making them an appealing choice if you’ve previously lost trees or plant life this way.
While a hungry deer will eat almost anything, deer will usually prefer other vegetation, so deer are unlikely to prevent your dogwood from growing well.
Are kousa dogwood a messy tree?
Yes. It’s probably the messiest of all dogwoods.
The kousa dogwood’s fruit is strawberry-like, compared with the flowering dogwood (and most other dogwoods) which are berry-like. If you’ve ever stood on one, you’ll notice it creates quite a mess on the pavement (and on your shoe).
You’ve also got to take into account the birdlife that these fruits attract. If the dogwood’s growing over your driveway, you’re going to have birds pooping on your car. Yet another reason to plant it at least 15 feet away from a driveway.
Do kousa dogwoods smell bad?
Dogwoods have a fairly strong scent when in full bloom (which can be for up to 6 weeks), but in most people’s opinion it’s not a bad smell at all – some liken it to honeysuckle. Many confuse it with the Bradford pear (which is known to smell bad) because of its similar flowers.
The kousa dogwood’s flowers don’t smell markedly different from other dogwood species and the scent not unappealing. All in all, the fragrance aspect is a pretty small element of owning a dogwood tree.
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Photo by David J. Stang, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
Henryhartley, CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons
Famartin, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons