When I planted my Acer griseum, it was for several reasons. Yes, there are its looks – it’s got that striking exfoliating cinnamon-brown bark and its vividly contrasting bluish-green trifoliate leaves that appear early and turn a long-lasting red in fall. It’s so attractive that it seems to get at least one photograph in every book about trees (and yes, I have quite the collection!). But perhaps the main reason was that it really doesn’t get too big – so many other trees are promised to be ‘small or medium’ but will end up dwarfing your house.
So exactly how fast do they grow, and how big do they get? This is something I researched heavily before I decided to plant one on my own property.
On average, paperbark maples grow to 25-30 feet (7.6-9.1m) in height and spread to 20-25 feet (6.7-7.6m) in width in ideal growing conditions. They grow quite slowly at 6 to 12 inches (30-60cm) per year, and reach their mature size between 25 and 50 years.
I always find these sizes much easier to visualize in comparison to other things! So try this. After ten years, your paperbark maple will be about the same height as a one-story house, and a bit wider than a driveway. Then after twenty years, it’ll be as tall as a two-story house and as wide as two or three driveways. In the following decades after that, it may get a little larger, putting on another few feet in height and spread.
Here’s one of my own photos, which is unusually useful for this article…
I photographed this paperbark maple in 2019. It was planted by Queen Elizabeth II’s husband Prince Philip, Duke of Edinburgh 70 years earlier in 1949 – there’s even a plaque to prove it! A beautifully compact tree – this one was about 25 feet in height and spread. The trunk’s about 10 inches in diameter.
Most trees of other species will far outgrow this size in 70 years. I see lots of tree butchery (especially tree-topping!) on properties near me as homeowners try in vain to control the size of the giants growing in their yards that were once planted as thin saplings.
I think this dense but cautiously-growing growing tree should be in a lot more yards. What an excellent choice – it’s also relatively free from diseases and tolerant of different soil types and pH levels. It can easily outlive a human lifespan – if you plant one of these, you’ve got the long game in mind.
Paperbark maple is considered endangered due to deforestation and destruction within its natural habitat. In 2015, a US team was sent to China to find specimens and return saplings for preservation. They covered a zigzagging route of 2,200 miles in their search! By growing one on your own property, you’re taking part in the ex-situ conservation of one of nature’s most beautiful trees.
“Of the many hundreds of plants I have observed and collected in China, none were more exciting than finding a grove of wild paperbark maple.”Paul Meyer, North America-China Plant Exploration Consortium
Why is my paperbark maple not growing? And how do I make it grow faster
So, I did say above that this size is expected in ideal growing conditions. Many things can get in the way. You might have noticed your Acer griseum isn’t putting on height as expected.
It’s worth pointing out that some paperbark maples are simply destined to end up at slightly different sizes.
Firstly, genetic factors are a large influence. Similarly, some will have bark that exfoliates and peels more than others (pro tip – this decreases with age, so when buying Acer griseum in a nursery, be careful to choose the one with the best peeling bark – it’s visible even in saplings).
There are actually a few cultivars that are sold in nurseries that might be predisposed to grow even more gingerly – Acer Griseum ‘Cinnamon Flake’ for example, which might not ever quite reach 20 feet in height.
Secondly, environmental factors. Since some of these are more amenable to hands-on gardening intervention, I’ll go through each one below, so you’ll know how to maximize the growth potential of your paperbark maple.
Paperbark maple growth and temperature
Acer griseum is a hardy enough tree. After all, it grows natively high in the high mountainous regions of central China. In the United States, it’s usually considered hardy to zone 5 – meaning it will survive where the ‘average annual minimum winter temperature’ is -20 to -15 °F (-28.9 to -26.1 °C). Practically this means all but the northmost parts of the US. This also means it will grow throughout most of the UK and Ireland and across Europe.
However, it’s probably best suited to a slightly warmer average temperature, perhaps around zone 7 or 8, where late frosts won’t limit the growth of new shoots in spring.
You can check where you are on the USDA plant hardiness map here.
Paperbark maple sun, soil and water requirements
Where on your property is your paperbark maple planted? If you’re going to see it thrive, a wide and open space is best. But the main requirement is full sun, so a sun-exposed south-facing site will do. It can put up with partial shade, but if you’ve put a young tree in a shaded spot, you may have better luck transplanting it to another site – it will probably be years before you realize that it isn’t growing as vigorously as it should, and by that stage, transplanting will be difficult.
They are very tolerant to different soils though- not picky about clay, loam, sand, or whether the soil’s acidic or alkaline. But pH 6-9 is probably ideal.
It likes soil that is moist and well-drained. Paperbark maples don’t deal well with drought. That’s why it’s important to keep it watered during dry spells, particularly in the first 3-5 years from planting. You may notice a wilt in the leaves if it starts to dry up, but it’s best not to wait that long. Simply dig your finger about an inch into the soil near the base of the tree – if none of the soil sticks to your finger or it feels dry, it’s time to give it some water.
Practically, once every 1-2 weeks should be enough, even during a hot spell, as long as it’s a good 30-minute soak. You’re aiming to water deep into the soil – not just to dampen the top layer.
Mulch, such as bark chippings, is important for the health of trees, particularly when young. A young tree should have at least a 5-foot diameter circle of mulch around its trunk. This keeps the roots cool and aerated and retains moisture – simulating the organic matter of a forest floor. It’s OK to have the mulch pile up slightly towards the center, as long as there’s a dip right where the trunk is (like a donut shape) – if the trunk is covered, it can contribute to trunk rot and fungal infections.
Acer griseum pests and diseases
Fortunately, the paperbark maple is relatively untroubled by disease and pests. The most trouble you’re likely to have is caterpillars eating the leaves, or possibly an aphid infection. Remove caterpillars by hand, and use insecticidal soap or aphid spray on the leaves if you can see any greenflies. These infestations are unlikely to affect the growth rate of this tree.
However, Verticillium wilt, which affects many trees, can infect Acer griseum too. It can cause prematurely browning and wilting leaves which may fall early. If this is happening to your paperbark maple, I would recommend consulting a trained arborist as soon as you can.
Fertilizing Paperbark maples – does it make them grow better?
Poor soil nutrient availability most certainly can be a reason for slower-than-normal tree growth. It’s an easy fix, and a little effort once a year can keep your tree looking healthy and growing by that reliable 6-12 inches a year.
If you’re applying fertilizer, do it just once a year around early March, as the new growth is beginning. I’d suggest a general fertilizer such as 12-4-8. You can easily buy these online. 12, 4 and 8 stand for the ratios of nitrogen, phosphorus and potassium (N, P and K) respectively. Fertilizers with higher nitrogen content are believed to stimulate the most woody growth.
It’s really interesting to check what your existing soil make-up is though. I use the Rapitest soil kit – it only takes a matter of minutes, and will also give you a pH reading. Knowing about your soil is useful for all your plants and trees, not just Acer griseum!
Do paperbark maples have to be pruned to help them grow?
This one’s generally a no! While pruning off lower branches will mean the tree will put more energy into root growth and the development of its crown, I would recommend keeping a ‘hands-off’ approach when it comes to pruning this tree (I know, ironic given the name of this site). The trunk is quite short, usually branching upwards a few feet off the ground.
If you really have to prune this tree, it should be only misplaced or crossing branches that get the chop. But do it when the tree is dormant in winter.
Growing paperbark maples from seed
Have you wondered why paperbark maples are so expensive in the nursery? It’s because they’re hard to propagate. Only around 5% of its seeds, if properly planted, will germinate and grow into a young sapling. This factor, together with habitat loss and deforestation in its native China, contributes to the paperbark maple’s status as an endangered species.
That’ll take more than 2 months in an appropriate seed compost, so a lot of persistence is required. If you find any seedlings growing near your tree, try to pot them up!
But since Acer griseum is auto-fertilizing and produces a lot of seed, your chances are good if you plant enough of them.
This video on Youtube goes through the process.
As I write, the winged fruit is ripening on my paperbark outside. I can’t wait to try this.