What to Add to the Soil to Get a Wisteria to Bloom

Soil Basics

• Wisteria requires the right soil mixture to grow and the right building blocks to bloom. Plant wisteria in moist, crumbly soil, but avoid rich amendments. According to the Ladybird Johnson Wildflower Center, rich, acidic soil leads to vegetative wisteria growth rather than blooming.

Amending and Fertilizing

• Mix 7 inches of quick-draining garden loam into the top 18 inches of natural soil in your planting site to produce a loose, moist and quick-draining foundation. Add 2 inches of organic compost to the tilled soil to add nutrition without producing too much acid. The Ohio State university Extension recommends giving wisteria superphosphate fertilizer (0-20-0) in early spring to nourish the plant and encourage blooming. Always follow manufacturer directions for fertilizer applications.

Site and Support

• Wisteria won't bloom if it doesn't get enough sun. Put the plant in a spot that gets six to eight hours of sun every day for full blooming. If you live in a cold growing zone, choose a spot that gets protection from winter winds and frosts. Give the wisteria a trellis, arbor or wall to climb, for better sun and air exposure in the summer.

Season and Hardiness

• Wisteria is a perennial and may live for many years but is only hardy to U.S. Department of Agriculture Growing Zones 5 to 8. The vine refuses to grow or bloom in hotter or colder areas of the country. Healthy wisteria produces flowers with new growth in late spring and early summer.

Considerations

• According to the Ohio State University Extension, some wisteria plants take longer to mature than others. This lengthy adolescence means delayed blooming. Heavy spring pruning also damages blooming on established bushes.