The Use of Lime on Poppy Plants

Lime in the Garden

• The pH or relative acidity or alkalinity of soil affects the ability of plant roots to absorb minerals in the soil and is also a factor in soil microbial activity. A pH of 7.0, in the middle of the scale, is considered neutral, sometimes called base. Most garden plants grow best in soil with a pH that's slightly acidic to neutral, from 6.0 to 7.5. You can determine your soil's pH with a home test kit or meter, or by sending a soil sample to your local extension service for analysis. Use horticultural-grade lime to "sweeten" or raise the pH of soil that's too acidic. Never add lime to your soil before performing a pH test.

About Oriental Poppies

• Oriental poppies (P. orientale) have been perennial garden staples for generations. Every spring, these sturdy plants form a basal rosette of foliage topped by tall flower stems. The flowers have delicate, crepe-like petals that shimmer in the sunlight. Poppy flowers are usually single but semi-double and double cultivars are available. There are red, pink, orange, purple and white poppies available, many with a dark blotch in the center. The flowers don't last long but the seed pods dry well for winter arrangements. Once flowering is finished, oriental poppies go dormant, so plant them near summer-flowering perennials, such as baby's breath and sunflowers, that can hide the fading foliage. Oriental poppies grow best in soil with a neutral pH of 7.0. They're hardy in USDA Plant Hardiness Zones 3 through 9, depending on the cultivar.

Other Poppies

• Many other poppies also prefer soil with a neutral pH. Iceland poppies (P. nudicaule) grow 12 to 24 inches tall and have white, orange, yellow, pink and red flowers throughout the summer. They're a good choice for rock gardens and are hardy in zones 4 through 10. Other poppies that thrive in neutral soils include the California poppy (Eschscholzia californica) and the Flanders poppy (P. rhoeas).

There's Always an Exception

• One of the most striking poppies is the Himalayan blue poppy (Meconopsis "Lingholm"). Native to Burma, Tibet and China, this lovely, clear blue perennial poppy grows best in moist, well-drained, acidic soil. It's only suitable for climates with cool and damp summers, such as in Alaska and the Pacific Northwest. If grown in neutral or alkaline soil, the flowers of the Himalayan blue poppy turn pink. Never lime the soil where you grow Himalayan blue poppies.

The Bottom Line on Lime and Poppies

• If a pH test on your soil shows that it's acidic, you need to add lime to the soil to raise the pH before you plant most types of poppies. Follow the package or extension service directions carefully for the amount to apply, since too much lime is as bad as not enough. Test the pH every year or two and if necessary, apply a side dressing of lime around your poppy plants to keep the soil neutral.