Ash are another familiar group of trees from temperate climates, though several species are native to subtropical areas as well. There are almost 100 species across the Northern Hemisphere, belonging to the olive family, Oleaceae.
In nature, ash trees generally grow in wet areas, often tolerating more waterlogged conditions than other other trees. Unfortunately, most species are not particularly heat or drought resistant. The majority of species from temperate areas do poorly here.
F. velutina, the velvet ash, or more commonly known by the name of its most famous cultivar, the 'Modesto' ash, is by far the most common species in the urban forest of Sacramento. It was briefly the most popular tree for developers to plant and is still seen in many neighborhoods developed during several decades in the mid to late 1900's. Unfortunately, it has proven very susceptible to several serious issues, most prominently mistletoe and anthracnose. Many are now dying across the city.
F. uhdei, the evergreen or shamel ash, is somewhat less common but does much better here. There are some remarkably large and beautiful specimens in older parks and campuses around town, though it does not seem to be planted much in recent years. It also naturalizes fairly readily.
F. angustifolia is the most popular species to plant currently, typically the cultivar 'Raywood'. While better than 'Modesto', this cultivar also has problems and tends to be short-lived.
F. latifolia, the Oregon ash, is a native species that can be seen along perennial streams and rivers in the area. It is not very drought resistant and is not usually used in horticulture.
Unfortunately, all of these species are probably susceptible to the emerald ash borer, which is an extremely deadly beetle introduced from Asia, which has just arrived on the West Coast. This pest has wiped our virtually all ash trees across the eastern half of the continent already, and is likely to do so in California in the coming years. For that reason, I strongly discourage planting any ash trees until this pest can be controlled. Predatory insects from its native range are being trialed currently, but their effectiveness remains to be seen.
In nature, ash trees generally grow in wet areas, often tolerating more waterlogged conditions than other other trees. Unfortunately, most species are not particularly heat or drought resistant. The majority of species from temperate areas do poorly here.
F. velutina, the velvet ash, or more commonly known by the name of its most famous cultivar, the 'Modesto' ash, is by far the most common species in the urban forest of Sacramento. It was briefly the most popular tree for developers to plant and is still seen in many neighborhoods developed during several decades in the mid to late 1900's. Unfortunately, it has proven very susceptible to several serious issues, most prominently mistletoe and anthracnose. Many are now dying across the city.
F. uhdei, the evergreen or shamel ash, is somewhat less common but does much better here. There are some remarkably large and beautiful specimens in older parks and campuses around town, though it does not seem to be planted much in recent years. It also naturalizes fairly readily.
F. angustifolia is the most popular species to plant currently, typically the cultivar 'Raywood'. While better than 'Modesto', this cultivar also has problems and tends to be short-lived.
F. latifolia, the Oregon ash, is a native species that can be seen along perennial streams and rivers in the area. It is not very drought resistant and is not usually used in horticulture.
Unfortunately, all of these species are probably susceptible to the emerald ash borer, which is an extremely deadly beetle introduced from Asia, which has just arrived on the West Coast. This pest has wiped our virtually all ash trees across the eastern half of the continent already, and is likely to do so in California in the coming years. For that reason, I strongly discourage planting any ash trees until this pest can be controlled. Predatory insects from its native range are being trialed currently, but their effectiveness remains to be seen.