Garden flowers with alkaline soil above 7.0 have a pH value. An increase in pH causes a reduction in the nutrients available for plant growth, resulting in some species not surviving. Iron is one of the major nutrients that become unavailable due to a high pH level. One benefit of having alkaline soil is that it warms up quickly so you can plant your specimens before spring time. Only soils with a heavy lime content, or chalky species, generally have an alkaline pH. A complete soil test will help you determine the pH value of your garden soil. Contact your County University Extension office for information on having a soil test flower in your garden. Make sure you have an individual test for each garden area, as the pH may vary in the past soil or species in the soil.
raise your garden properly by working in 2 to 3 inches of organic compost 6 to 8 inches into the soil before planting. This will nutrient value and increase the ability of the soil to hold moisture in hot summer temperatures. Adding organic soil to your garden soil will change the consistency, but it does not adjust the soil pH. Soil pH can be adjusted with chemical amendments, however this is a time consuming process for each source to keep the pH below 7.0. If you have alkaline soil and don’t want to add maintenance chemical amendments each year, label the plant to verify that it will grow in alkaline soil with a pH above 7.0.
Trees that are tolerant of alkaline soils include; maple, honey locust, Rose of Saron, oriental red cedar and English oak. All varieties of maple, including Japanese ornamental maples, are tolerant. Hardiest species and honey locust does best in USDA Tardiness Zones 3 through 9. Grows warmer than maple varieties. temperatures in Zones 6 through 9. Rose of Sharon, also known as Syrian Hibiscus, and English oak prefer to grow in USDA hardiness. Zones 5 through 9. Red Easter cedar is a cold tolerant tree that survives in USDA hardiness zones 2 through 9
Evergreen shrubs that grow well in alkaline soil with a pH above 7.0 include California lilacs, green velvet box and Photinia shrub species. California lilac grows best in USDA hardiness zones 8 through 10. Green boxwood is slightly more cold tolerant than USDA hardiness zones 6 through 8. Photinia shrub species grow best in Zones 7 through 9.
Deciduous shrub species that prefer alkaline soil include Lilacs, Weigela, Forsythia and Spiraea shrubs. Weigela bushes grow best in USDA hardiness Zones 5 through 9, while Forsythia species grow best in Zones 6 through 9. Spiraea shrubs are a popular variety grown in northern areas Units because they tolerate colder temperatures in USDA hardiness Zones 3 through 8.
Perennial plants species that like alkaline soil include Dianthus, Clematis, Scabiosa and Potentilla plants. Dianthus species, also known as pinks, grow well in the Midwest in areas where USDA hardiness zones are 4 through 10. Clematis is another Cold favorite because it grows best in USDA hardiness Zones 3 through 8. Prefer hardy and potent species “.
It is always best to know the USDA Hardiness Zone of the tree, shrub or perennial to plant to make sure you want a hardy plant for your local location.
http://www.ipm.iastate.edu/ipm/hortnews/1994/4-6-1994/ph.html
Iowa State University Distance: How to Change Your PH
http://web1.msue.msu.edu/monroe/soilweb2/alkaline-tolerant.htm
Michigan State University Extension: Alkaline Tolerant Plants
