ISA Certified Arborist, PR4600A I did a tour around to update my photo files. I thought it would be fun to put together a piece on the varied types of Maples found growing here in Lethbridge. I probably should have waited until the Canada Day Weekend but you may want to plant your own patriotic tree before then. Maples are one of my favorite trees since most are fast growing and variety of sizes means you can find one to match most urban lots. Pruning should be limited to July/August when you won’t initiate sap flow at the pruning site. This collects dust, attracts wasps and taxes your tree. Sizes below are a guideline since pruning can modify height and spread but it CANNOT make a big tree small. These are thirsty trees – deep regular watering a must to keep them healthy.
Maples are fast growing trees and range in height from 6 meters to 25 m. Many of the newer cultivars are better suited to city living. All have samaras (which are winged seeds). On some varieties they turn an incredible shade or pink or red. They require full sun (6 hours per day) and moist, slightly acidic soil. Some are tolerant of saline soils. Leaves are varying shades of green with one deep burgundy. Leaves and twigs grow opposite each other. Yellowing leaves is a sign of nutrient deficiencies in the soil. The roots are shallow and wide spreading and can sometimes become invasive. The seeds self sow which may mean you have several baby trees to deal with in places you’d rather not. Fall colors range from bright orange to brilliant red. There is bound to be a maple to suit your space. A very hard wood, the natural staining within the wood and development of burls makes is a desireable product for wood turning and carpentry.
They are prone to some insects and diseases. I have tried to list a few with the species.
MANITOBA MAPLE (Acer Negundo)
Originally, the only form of Maple found in our area was the Manitoba Maple (or Box Elder). The leaves don’t fit our image of a maple – it is a compound leaf made up of leaflets. It features plain samaras that self-seed readily which is why it is sometimes identified as a weed tree. (10 m x 7 m)
It is known for the red staining on the inner wood. It features irregular trunk development called burls. These two features make it very desirable for wood turning and wood crafts.
Most commonly found in older Lethbridge Neighborhoods and Parks. New cultivars “Sensation” offering orange fall foliage .
CRIMSON KING NORWAY MAPLE (Acer platanoides “Prairie Splendor”)
Slightly slower growing. Pretty Yellow Flowers. (10 m x 8 m)
NORWAY MAPLE (Acer Platanoides)
This is the most mature example I can find (about 60 years of age). It had a substantial crown raising in the past year and all the lower branches were pruned off. Hard to find pure Norway stock for sale.
AMUR MAPLE (Acer ginnala)
A very hardy, fast growing small tree (6 m x 5 m). Show stopping hot pink flowers followed by pink winged samaras. Growing successfully throughout the City. Tolerant of saline soils – pH imbalance may result in yellowing leaves. Photos show multi-stem form and the pink seeds. Subject to Tar Spot. Red fall color. Elongated narrow leaf form. Available in tree (single stem) or shrub (multi-stem) forms. Left to grow, both will form a ‘tree’).
SUGAR MAPLES (Unity Acer saccharum ‘Jefcan’) Yellow, Orange fall color 12 m x 9 m
SILVER MAPLE (Acer saccharinum) The largest of the maples in our region. (12-15 m x 9-12 m). Silver grey bark. Extensive Root system. NEEDS A BIG SPACE and lots of water. Golden fall color.