Posted by Brent Wilson on 8/1/2017 to FAQ (Frequently Asked Questions)
First, I have to make a confession regarding the title of this article. In a way, the title is misleading in that it might make one think there's a way anyone can know for sure the size a specific type of plant or tree will grow to at maturity in a specific area, climate or environment.
So, we fall in love with a specific plant we don't know much about but are interested in adding it to our garden. But first, before spending the dollars and time and effort to plant it, we want to know for sure it will fit the space we intend it to fill in our garden. That's when we might go on a search for websites that list the "mature sizes" of our plant. We go to one source and they list the plant we want as maturing to 10 feet tall and wide. Then, just to be sure, we go for a second opinion to a different reliable source and it list's the mature size of the same plant at 15 feet tall and wide. That's a difference of 5 feet, which might make it too large for the place we intend it to fill. Now we're confused. But we really want the plant so we check a few more sources and find that every site we go to lists a different mature size. Now we're really confused, and maybe upset. Which one is right? Maybe none...maybe all.
When it comes to mature plant size, what it really comes down to is that the same plant might grow to significantly different sizes based on local climate, environmental factors, and average lifespan of the specific plant.
As long as a plant is alive and well it will put out new growth every spring, or at sometime during the year, thereby adding to its size. Only when in poor health does it completely stop growing. Because a specific type of plant might live 30 years on average in one area or climate and 50 years in another area or climate, it's impossible to know or state the mature size. This is why sizes listed by various sources are often based on the average lifespan of a specific type of plant, or the average size a plant might grow to at a specific age. For example, many sources list the size you might expect specific Japanese maple cultivars to grow to by age 10.
Local climate and other environmental factors can also determine the size a plant will grow. A specific type of plant, such as bamboo, might grow half the size in a cool climate as it would in a warm climate. A plant growing in dry conditions might grow much smaller than it would in moist conditions. Sun exposure, soil type, soil drainage, elevation, fertilization, pruning and other environmental conditions and care practices are factors as well. Therefore, it's virtually impossible for any nursery professional, arborist, landscaper or veteran gardener to state the exact mature size any specific plant will grow to in a specific area.
So, what to do?
Here's what you can do to come as close as possible to knowing the average size a specific plant type will grow to...
First, take a look around your local area to find old landscapes that might contain established specimens of the specific plant or tree you would like to add to your landscape or gardens.
If you can't find any older specimens growing in your area, consult with reputable local nursery professionals, landscapers, arborists, Extension service personnel, or Master Gardeners who might be able to give you a good idea as to the mature size you might expect for a specific plant.
Posting a question in a gardening forum or on a social media channel can sometimes be helpful, though doing so might end in an ego battle as to who has the "right" answer.:-) I'd still suggest consulting with local professionals in your area first.
Regarding plant sizes and other attributes, I know from experience that the complete information is sometimes impossible to find for any given plant. That said, we at Wilson Bros Gardens do our best to provide the most accurate information possible based on our own 40 years of personal experience growing plants in our own gardens here in north-central Georgia, USDA Zone 8a. That said, we do offer many relatively new plant species and cultivars so often have to rely on information published by plant breeders regarding size and other attributes of a plant, which may or may not be entirely accurate.
Please Note: We at Wilson Bros Gardens know we are not perfect. Sometimes we make typos or other unintentional errors in the content published on our website, or we may have overlooked updates. If you look at the plant descriptions on this site and think you've found an error in content please contact us with details or updated information so we can make a correction if necessary. Thanks!
Hope this info was helpful. Let us know if there's ever anything we can help you with.
Plant Long & Prosper!
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