| General Description | The ‘Emerald Queen’ Norway Maple is an all-around phenomenal tree for the urban landscape. It is salt resistant, pollution resistant, adaptable to almost every soil type, and looks quite attractive during spring, summer and autumn. This tree is one of the most popular Norway Maple cultivars, and possibly the most widely available. Although this tree makes such a strong case for itself, we are now aware of the invasiveness potential with this species and should no longer plant it in North America. The majority of Norway Maple cultivars are able to aggressively reseed, having the same impact. This includes the ‘Emerald Queen’ Norway Maple. |
| ID Characteristic | This cultivar has very dark, lustrous green leaves, followed by a stunning, beautiful yellow in the autumn. It has an upright shape, moving to round-oval upright in maturity. Nearly identical crowns between individual specimens is quite common. Buds have a purple-pink hue that is not present in standard Acer platanoides. |
| Shape | An Oval-Rounded crown, with ascending branches. At young ages, the lateral branches will always grow upright. Different individuals develop nearly identical upright, rounded forms. |
| Landscape | The Emerald Queen makes a wonderful street tree, shade tree, specimen tree, or lawn tree. This hardy cultivar is also well suited for parking lot islands, highway medians, and any place it can show off its strong urban tolerance. |
| Propagation | Most common form of propagation is done through grafting the ‘Emerald Queen’ cultivar on a rootstock. The most common rootstock used is standard Acer platanoides. Many arborists claim never experiencing any incompatibility problems using A. platanoides rootstock. |
| Cultivation | The ‘Emerald Queen’ Norway Maple is a very easy tree to transplant, with many arborists reporting successful transplants at maturity. Pruning with this tree is very minimal, especially at young ages when the lateral branches will never droop. Prefers well-drained soils in full sun. Will successfully grow in sand, loam, and clay soils, as well as tolerate both alkaline and acidic soils. |
| Pests | This cultivar is susceptible to Verticillium Wilt, which if untreated is usually fatal. It is also susceptible to Leaf Scorch in extreme heats. Maple Tar Spot is extremely common in the species, this cultivar is no exception. If put under stress, various types of borer including Leak Stalk borer and Petiole Borer can cause serious damage. Pests are usually not serious enough to affect the long-term health. |
| Notable Specimens | Oxford Drive, University of Western Ontario main campus. This street is lined with 10 -30 Emerald Queen Norway Maples, presumably planted before we were made aware of the tree’s invasive potential. |
| Habitat | The species can be seen growing in many different environments across North America, where it is now considered invasive. The ‘Emerald Queen’ cultivar is regarded as hardier and more reliable in extreme conditions than Acer platanoides and most other cultivars. The ability for the species and many of its most popular cultivars to reseed and form thick canopies, in combination with its environment adaptability, is what poses such a threat to native species. |
| Bark/Stem Description | New growth is smooth, shiny, and brown. Quite easy to identify on the tree. Mature bark is very course and brown-grey to medium-light grey. Running your hand down a mature trunk would feel quite rough and bumpy, possibly scratching your skin and flaking chunks off the trunk. This tree does not develop any type of thorns. |
| Flower/Leaf Bud Description | This tree has very large, rounded buds, dark brown to chestnut in colour. The buds have a purple/pink tone to them that does not appear in standard Acer platanoides. The terminal buds are 0.5 – 1.5 cm long, 0.75 cm wide. Buds are ovoid, showing 3-4 scales. |
| Leaf Description | Arranged oppositely, the tree has simple, palmate, lobed leaves. The leaves are usually 5-lobed, anywhere from 10 – 15 cm across, and equally as long. The lobes are acuminate. Through the growing season the tree will have deep, lustrous green leaves that transition to a beautiful, stunning yellow in the autumn. |
| Flower Description | Beautiful yellow to greenish-yellow flowers, appearing in many small corymb clusters. The tree flowers in early spring (March – April), before the foliage, adding to the visual appeal. The small flowers do present ornamental value, although this lessens if the flowers are more green than yellow. |
| Fruit Description | The ‘Emerald Queen’ produces mature samaras in late summer to early autumn. The samaras average 3.5 – 4 cm long. The wings of the samara are green, fading to brown as you move up the fruit. They are dry, hairless and slightly rough to touch. The ‘Emerald Queen’ Norway Maple is able to reseed in rates similar to Acer platanoides, meaning it also has extreme invasive potential. |
| Colour Description | The tree has beautiful, dark green leaves through the growing season, followed by a stunning yellow colour in autumn. New growth is brown with mature bark being brown-grey to grey. The bark of the tree does not spark any interest. |
| Texture Description | New growth has shiny, smooth bark. Course, rough appearing texture once the tree is through its youth. |