my tree does not grow. it is in clay. the leaf edges turn brown half way thru the summer. it is in full sun and it gets watered regularly. it is eight years old and has always done this.
Thank you for your question about your Harlequin maple ‘Drummondii’ – a cultivar of Norway Maple (Acer platanoides).
The symptoms you describe sound like leaf scorch, a condition in which the leaves are losing water to the atmosphere faster than they can obtain it through the tree’s roots and tissues.
There could be many reasons for this drought stress: girdled roots (the roots are wrapping around themselves and aren’t able to take up moisture); environmental pollution; compacted soil; improper planting (too shallow or too deep); too much water (which removes oxygen from around the roots and suffocates them); too little water; inappropriate sunlight levels; a site that is too exposed or windy; a secondary disease that contributes to the problem, etc.
Since you say that your tree has always had these symptoms, the most likely issue is that the tree was improperly planted and/or cared for to begin with. Note also that maples are slow-growing trees in their first several years, so that may be part of the reason you are not seeing the kind of growth you might have hoped for. It’s also possible that the Harlequin variety is slower-growing than the straight species.
Your best bet now is to consult a certified arborist – they could suggest a course of treatment, or they may recommend removal of the tree.
As you may know, Norway maples produce many seedlings and are considered invasive in southern Ontario. The Ontario Invasive Plant Council has this to say about cultivars of Norway maple that some suggest are less invasive:
“Several studies have investigated the invasive potential of cultivars compared to the species by documenting differences in seed production and viability among cultivars. There are several cultivars that produce significantly less seed, such as ‘Crimson King’, ‘Globosum’, ‘Faasen’s Black’, and others with low seed germination and viability, such as ‘Columnare’ … It has been suggested that planting cultivars with low seed yield and viability is a way of reducing the potential for invasion. However, there is concern that cultivars can still be invasive. Cultivars do not produce true-to-seed cultivar seedlings and will instead revert to the original Norway maple species … Cultivar seedlings have been known to spread along fences, hedges, ditches, concrete cracks, and boulevards.” Ontario Invasive Plant Council – Best Management Practices_Norway Maple
If removal of the tree is the recommended approach, there are many native trees you could consider, or non-natives that are not invasive.
The below resources should be a good starting point.
Good luck!
ISO Ontario – Hire a Certified Arborist
Colorado State University – Leaf Scorch
Maple Leaves Forever – Leaf Scorch on Young Maples (this site provides care advice for native maples that is equally applicable to Norway maples)
City of Toronto – Threats to Trees: Diseases
Grow Me Instead – Ontario Invasive Plant Council
Planting a Tree for Life: A Toronto Master Gardeners Guide