My 20ish year old Harlequin Maple has about 20% of it’s leaves 100% white/yellow. They look healthy, the tree looks healthy but It has never had all white/yellow leaves before. Does it need anything??? is this normal????
Thank you for contacting the Toronto Master Gardeners with your interesting question concerning your Harlequin Maple Tree.
Harlequin Maple, Acer platanoides ‘Drummondii’ is a variety of Norway maple which possesses attractive white-variegated light green foliage, and as an added bonus, these leaves turn yellow in the fall. These trees grow 50’ tall at maturity with a spread of 40’. Harlequin maples do like sun, but do best in a somewhat sheltered location, protected from the midday sun and drying winds. It prefers to grow in average-to-moist conditions, and shouldn’t be allowed to dry out. It is not particular as to soil type or pH.
Normally, we receive questions concerning the loss of variegation, and reverting to all green leaves. Branches with all green leaves having considerable more chlorophyll than the variegated leaves, will eventually outgrow the desired variegated ones and they will quickly outcompete the variegated leaves.
Variegation in plants can be a result of an anomaly (mutation) or the result of carefully engineered breeding. The all white/pale yellow leaves contain considerably less chlorophyll, which means that these leaves produce less food through photosynthesis. In general, variegated plants tend to be less hearty and vigorous as compared to their completely green cousins. In some cases some plants can produce albino growth. Albinism has been know to occur in variegated Euonymous. This type of growth cannot gather solar energy and will eventually die back. Plants require chlorophyll to produce food and survive: if all the new growth becomes albino, the plant will not survive. In the case of Euonymous, the total albino growth is removed.
Alternatively, chlorosis, a yellowing of normally green leaves due to a lack of chlorophyll can be the result of numerous factors, either singly or in combination. Poor drainage, damaged or compacted roots, high alkalinity, nutrient deficiencies such as lack of nitrogen or drought are a few factors. The past few days of extreme heat and lack of rain may have contributed to an increase in these occurrences.
The following information from Michigan State University may be of interest: “Some nutrients that trees need to produce chlorophyll, including iron and manganese, may be deficient or depleted in the soils of some local areas. In other cases, excess potassium or phosphorus may actually limit accessibility of these critical nutrients. A principal cause of nutrient availability, however, is soil pH. Soils can be either acidic or alkaline, typically ranging from extremes of 7.5 (highly alkaline) to 4.5 (highly acidic) on an overall scale of 0 to 14. Urban soils in particular are more likely to be more alkaline, as are areas of the state with limestone bedrock. Sandy soils and special features like bogs are more acidic. In either case, if soils are above 6.5 or below 5.0, the nutrients needed for healthy chlorophyll production may be limited. The Morton Arboretum’s site contains more information on important soil characteristics.“
Our Toronto Master Gardener’s Garden Guide on Soil Fertility contains in depth information on soil health, and how and where, you can get your soil tested.
You may also wish to have your tree looked at by a certified arborist. To find a certified arborist in your area click here.