Fairly fast-growing trees, most of which tolerate hot summers, cold winters, and many kinds of soil, including alkaline sorts. Chiefly used as street, shade, lawn, and patio shelter trees. In most cases, leaves are divided into leaflets. Male and female flowers (generally inconspicuous, in clusters) grow on separate trees in some species, on the same tree in others. In the latter case, flowers are often followed by clusters of single-seeded, winged fruit, often in such abundance that they can be a litter problem. When flowers are on separate trees, you’ll get fruit on a female tree only if a male tree grows nearby.
Ash trees are prone to borers. In some parts of California, ash whitefly is a problem; these chalky white, 1/8-in.-long insects colonize in patches on leaf undersides. Outbreaks are usually controlled by natural enemies; avoid spraying with broad-spectrum insecticides, which are likely to wipe out these beneficial predators.Fraxinus latifolia
Native to Sierra Nevada and west of the Cascades from Northern California to British Columbia. Grows to 40–80 ft. tall, 30–50 ft. wide. Leaves 6–2 in. long are divided into five to seven oblong to oval, light green, hairy or smooth leaflets; the end leaflet reaches 4 in. long, larger than the side leaflets. Male and female flowers on separate trees. Will grow in standing water during winter months. Needs no dry-season irrigation. Subject to many pests and diseases; not a first-rate tree.
Grows to 3–4 ft. tall and 5–6 ft. wide (has reportedly reached 6 ft. tall and 10 ft. wide)...
California native. Satiny, lavender-pink flowers on 1–2-ft. stems in late spring. Spreads freely...
Deciduous in coldest areas, nearly evergreen elsewhere. This species originated in cultivation (not in...