Numerous tree species can be grown in alkaline soil conditions. Alkaline soil has a pH higher than 7.0 and is often referred to as "sweet" due to its lack of acidic ("sour") qualities. The soil is most prevalent in areas of low rainfall that receive less then 20 inches annually. Typically, alkaline soils have high limestone content and deficiencies in manganese and boron. Most trees that will thrive in alkaline soil can also be maintained in drought conditions.
The American linden (Tilia americana), also called the basswood, is a popular shade tree that can thrive in alkaline soil. It does not have drought tolerance, however. In early summer, the tree produces an abundance of yellow, fragrant flowers that bees enjoy. Honey made from the linden tree is considered to be the best in the world, according to the North Dakota State University The tree enjoys full sun or partial shade and has attained heights of up to 75 feet with a width of 64 feet. The American linden is a popular windbreak. No serious pests plague the tree and it is relatively hardy.
The Colorado spruce (Picea pungens) tolerates mildly alkaline soil conditions with a pH that hovers about 7.5. The tree will withstand drought but prefers moist soil and full sun. Birds enjoy spending cold wintry days within the tree's boughs. The tree can grow from 30 to 40 feet. Throughout many states, the Colorado spruce is a popular Christmas tree choice and commercially grown at farms to meet the needs of the public each holiday season. Numerous pests such as the whitefly, spruce needle miner and yellow-headed sawfly often plague the tree.
The pawpaw (Asimina triloba) will tolerate alkaline soil conditions. The tree can be grown in full sun or shade. Native to the eastern United States, the pawpaw fruit was a popular food for Native Americans and early European settlers. In order to set fruit, the tree must have a minimum of 400 chill hours per season with 160 days that are frost free, according to the California Rare Fruit Growers. The tree grows to a height of 20 feet. From March to May, the tree produces deep maroon blossoms that measure 2 inches across. Pawpaw fruit is thin-skinned, large, seeded and sweet. It can be easily eaten raw and is often compared to a mango (the fruit tastes like banana custard, and the fruit is sometimes called "poor-man's banana"). The tree is hardy and relatively pest free.
The Green ash (Fraxinus pennsylvanica) will grow to 60 feet. The tree is known for its fast growth rate even in alkaline soils. It prefers to be planted in full sun to partial shade. Greenish-yellow blossoms are produced in the spring. Flat, elongated seed pods are produced following flowering and provide a much needed winter diet for birds and mammals. Young trees are often plagued by ash borers, but the tree is relatively hardy and pest free. The bark of older trees often appears to be somewhat scaly.