White ash is a species of ash tree native to North America. Its leaves turn distinctly bright yellow or red in the autumn. *Fraxinus americana* is a fast-growing pioneer species that often inhabits riparian zones, and fragmented and disturbed habitats. It is similar in appearance to green ash (Fraxinus americana) and sometimes it is hard to tell between the two.
Table of contents
I. Appearance and Characteristics
Fraxinus americana, the white ash or American ash, is a fast-growing species of ash tree native to eastern and central North America.
The species is native to mesophytic hardwood forests from Nova Scotia west to Minnesota, south to northern Florida, and southwest to eastern Texas. Isolated populations have also been found in western Texas, Wyoming, and Colorado, and the species is reportedly naturalized in Hawaii.
There are an estimated 8 billion ash trees in the United States – the majority being white ash trees and green ash trees. White ash trees are threatened by the spread of the invasive emerald ash borer (Agrilus planipennis), detected in Detroit, Michigan in 2002 and now found in eastern Canada and the majority of U.S. states, whose larvae kill ash trees.
The name white ash derives from the glaucous undersides of the leaves. It is similar in appearance to the green ash, making identification difficult. The lower sides of the leaves of white ash are lighter in color than their upper sides, and the outer surface of the twigs of white ash may be flaky or peeling. Green ash leaves are similar in color on upper and lower sides, and twigs are smoother. White ash leaves turn yellow or red in autumn. Despite some overlap, the two species tend to grow in different locations as well; white ash is a forest tree that commonly occurs alongside sugar maple while green ash is a pioneer species that inhabits riparian zones and disturbed areas. The white ash’s compound leaves usually have 7 leaflets per leaf whereas the counts in other ash trees more often vary.
Like other species in the section Melioides, Fraxinus americana is dioecious, with male and female flowers produced on separate individuals.
II. How to Grow and Care
Sunlight
White ash prefers full sun and can grow in a slightly shaded environment. plant it in an open location that provides at least 6 hours of sunlight per day. If sunlight is insufficient, it will grow poorly and bloom sparsely. However, if white ash is not leafy enough, its trunk will get sunburned when the summer sunlight is strong.
Temperate
White ash is widely distributed in temperate and subtropical regions of the northern hemisphere. It prefers cool, moist environments. It is resistant to heat, and can tolerate temperatures. Moist environments allow white ash to grow better. It can also tolerate waterlogging and drought.
Watering
It is best to water white ash daily when it has just been planted to encourage root growth. Once white ash has successfully taken root, watering once a week is enough. When the weather is dry and the tree is growing vigorously in summer, increase the frequency of watering. Before the ground freezes in late fall or winter, water once and then stop. This will provide the water it needs throughout the winter. Do not overwater the plant, as this could waterlog the soil and induce root rot.
Soil
White ash can grow in many types of soil. It likes soil with sufficient nutrients. The soil pH is not important; it can survive in a variety of pH levels, from alkaline to acidic. White ash prefers soil with good drainage, but can also tolerate drought and standing water.
Fertilizing
White ash can tolerate infertile soil, but adequate nutrients promote healthy growth and reduce the possibility of pests and diseases. Apply a slow-release fertilizer (10:10:10 ratio of nitrogen, phosphorus and potassium) once every fall, and give plenty of water afterward. This will promote nutrient uptake and prevent the fertilizer from burning the roots. If your white ash is planted in spring, fertilize it in late summer; if it is planted in fall, fertilize the second spring. Because the roots of newly planted trees are weak and cannot absorb nutrients well, too much fertilizer may cause root burn.
Planting Instructions
Transplant white ash before it sprouts in the spring, so it is more likely to establish itself. First, choose a sunny, open area that provides plenty of space for it to grow. Mature white ash can grow to average heights of 12 to 18 m, so you should make sure there are no walls or other trees nearby that will prevent it from growing. Dig a hole as deep as the soil mass that encases the plant roots and twice as wide as the root mass. After planting, compact the soil and water it well.
Pruning
Prune white ash in fall so the pruning wound can heal before the plant goes dormant in winter. Pruning also prevents winter rain and snow from crushing the branches. It is best to prune young trees every year and prune mature white ash every few years. Do some pruning regularly, such as removing some dead or diseased branches. When pruning, make sure to remove branches that are overgrown or crossed over. This promotes air circulation and prevents disease. If your white ash is particularly tall, it’s best to have it pruned by a professional.
Propagation
White ash trees can be propagated by seed or by cutting. Take cuttings in spring or summer, when the tree is less stressed. When cutting in summer, shade the tree to prevent excessive evaporation of water. Choose branches that grew in the current or last year, and cut 15 cm branches, preferably with 3-4 buds. Insert them into moist, sandy soil, and they will take root within 8 weeks.
The sowing process is complicated and white ash trees need a long time to grow, so propagating by sowing is not usually recommended. If you want to sow white ash, do it in spring, and start in a pot. Place the seeds in 1.3 cm-deep soil and cover them with plastic film. Store the pots in a refrigerator for three months. Next, place it on a heating mat (or somewhere else) and keep it at 21 to 24 ℃ for three months. During this period, make sure to keep the soil moist. The seeds will germinate within six weeks.
Transplanting
As a perennial plant, transplanting white ash thrives when done from mid-spring to early summer, the perfect season due to stable temperatures and ample sunlight. Choose a well-drained location with partial to full sunlight for optimal growth. Ensure proper spacing when transplanting to promote healthy air circulation.
Pests and Diseases
Hymenoscyphus fraxineus is a fungal disease that attacks ash trees. The disease causes leaf loss, crown dieback, and lesions in the bark. This fungus is, for the most part, fatal, both directly and indirectly, by weakening the tree’s immune system so that it is more susceptible to attacks from pests or pathogens. Because of this, younger trees are more affected, and fully mature ash trees are incapable of living long enough to reproduce. The disease has spread over most of Europe and has been confirmed in Britain, however, it has not yet been found in North America. The scale of the threat is not yet known, but is thought to be able to cause significant damage to the ash landscape of Europe and the UK.
III. Uses and Benefits
White ash is one of the most used trees for everyday purposes and, to keep up with high demand, is cultivated almost everywhere possible. The wood is white and quite dense (within 20% of 670 kg/m3), strong, and straight-grained. Its species produces an ideal, atypical dominant excurrent structured crown. It is a traditional timber of choice for production of baseball bats and tool handles. The wood is also favorable for furniture and flooring. A study compared it to eight other different species, and it showed the highest antibacterial activity in the context of manufacturing chopping boards.
Woodworkers use the timber mainly for interior uses due to high perishability in contact with ground soil. It is also used to make lobster traps. Since the 1950s, it has also become a popular choice for solid electric guitar bodies. It makes a serviceable longbow if properly worked. The wood was used in ceiling fan blades from the 1970s through the mid-1980s, though cane was sometimes simulated with plastic then. It is no longer used for ceiling fan blades in most countries.
White ash is not seen in cultivation as often as green ash, due to its preference for undisturbed forest sites away from urban pollution and soil compaction. It sometimes has been planted for its consistently reliable autumn colors, which typically are bright orange and red hues as opposed to other species of ash that produce a uniform yellow color.
North American native ash tree species are used by North American frogs as a critical food source, as leaves that fall from the trees are particularly suitable for tadpoles to feed upon in ponds (both temporary and permanent), large puddles, and other water sources. Species such as red maple, which are taking the place of ash due to the ash borer, are much less suitable for the frogs as a food source—resulting in poor frog survival rates and small frog sizes. The lack of tannins in the American ash variety makes them a good food source for frogs, but are not resistant to the ash borer. Varieties of ash from outside North America typically have much higher tannin levels and resist the borer. Maples and various non-native invasive trees, trees that are taking the place of American ash species in the North American ecosystem, typically have much higher leaf tannin levels. Ash species native to North America also provide important habitat and food for various other creatures that are native to North America.
IV. Harvesting and Storage
If you want to collect white ash seeds for planting, harvest the fruit in the fall when it turns from green to tan. The dried seeds can be stored at room temperature for 3-5 years.
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