How to Grow Poppies

Which poppies this guide covers

These are the annual poppies sown from seed each year: the Shirley, corn or Flanders poppy (Papaver rhoeas), the breadseed or peony-flowered poppy (P. somniferum), the California poppy (Eschscholzia californica) and the Iceland poppy (P. nudicaule), which LSU AgCenter groups with them because it is handled the same way in the South. The perennial Oriental poppy is a different plant, planted and divided in fall like other perennials.

Shirley poppies grow 2 to 3 feet tall with papery 3-inch flowers in red, pink, orange, white and bicolors. UT Gardens in Tennessee describes breadseed poppies reaching 3 to 4 feet by May, topped later by big seed pods. California poppy is shorter, closes its flowers at night and on cloudy days, and thrives on little water once established.

Sow them where they will flower

Poppies resent having their roots disturbed, so Cornell, Utah State, LSU AgCenter and UT Gardens all recommend sowing seed directly in the bed. Transplanted seedlings often sulk or fail, which is a common reason for a poor stand.

Timing matters more than anything else. Utah State found that the seed germinates better after freezing and thawing, so sow in late fall or very early spring. In cold-winter regions, a late-fall sowing sits dormant and sprouts when the soil thaws. If you sow in spring instead, go as early as you can work the ground, roughly 4 to 6 weeks before the last frost; the dates for your zone above show that window. Poppies stop flowering when summer heat arrives, so a late sowing gives short plants and a brief show.

In mild-winter areas, poppies are a fall crop. LSU AgCenter tells Gulf South gardeners to sow in October or November because the plants need the winter to build strength. Spring sowings there rarely put on a good show. The When to Plant Poppies page covers timing region by region.

How to sow

Prepare a fine, weed-free seedbed in full sun. Utah State suggests preparing the soil the fall before a spring sowing, so you are not working wet ground in March.

1. Mix the seed with a cup or so of dry sand. Breadseed poppy has more than 100,000 seeds per ounce, and the sand lets you see where you have sown and spreads the seed evenly.
2. Scatter it over the bed or along shallow furrows and press it in. Cover with no more than 1/8 inch of soil.
3. Keep the surface moist, with a fine spray that will not wash the seed away, until seedlings appear. Cornell gives 10 to 14 days to emergence for Shirley poppy at about 55°F. Utah State reports 7 to 28 days for breadseed poppy, about four weeks in cold soil and two weeks when it is warmer.
4. Thin before the seedlings are 6 inches tall. Penn State lists 6 to 12 inches between poppy plants and 6 to 8 inches for California poppy. Crowded plants flower poorly and invite mildew.

Soil, water and feeding

Well-drained soil is not optional. Iowa State notes that wet soil in winter makes poppies decline, and the UC Statewide IPM Program lists root, stem and crown rots among their main problems. Raised or sloped beds help on clay.

Poppies do not need rich ground. The University of Georgia recommends California and Iceland poppies for poor soils. Utah State caps compost at about 1 inch per 100 square feet and suggests a soil test before adding fertilizer. Feed lightly until the plants are established, then stop.

After thinning, water needs are modest. Utah State puts it at about 1 inch a week depending on weather. In California’s Mediterranean climate, Napa County Master Gardeners rarely water fall-sown California poppies except in a very dry year.

Poppies compete poorly with weeds while young. Weed by hand or cultivate very shallowly, then mulch with leaves or grass clippings once the plants are up.

Deadheading, reseeding and cutting

Removing faded flowers before pods form keeps plants blooming longer. If you want poppies again next year without sowing, leave a few pods to ripen and shed seed. Self-sown seedlings will appear in fall in the South and in spring in the North. Different colors cross freely, so volunteers may not match their parents.

Poppies make good cut flowers if you seal the stems. Cornell’s method: cut in the garden, recut indoors, then dip the stem ends in boiling water for 20 to 30 seconds or sear them with a flame. California poppy is the exception. Its petals drop quickly, so leave it in the garden. The ripe pods of Shirley and breadseed poppies dry well for arrangements.

Saving breadseed poppy seed

Harvest in dry weather once the pods turn leathery and the seeds rattle. Tip the pods over a bag and shake out the seed, repeating every week or so as more pods ripen. Utah State expects 4 to 5 ounces of seed from a well-grown 10-foot row. Seed for baking keeps its flavor a long time, but viability drops fast, so replant saved seed within a year. To keep a variety pure, Utah State says to grow different varieties at least 250 feet apart or hand-pollinate and bag the flowers.

Varieties extension services recommend

For the Midwest, Iowa State suggests the Shirley poppies ‘Mother of Pearl’ (pastels) and ‘Red Legion’, the breadseed poppies ‘Danish Flag’ and ‘Black Peony’, and the Iceland poppies ‘Champagne Bubbles’, ‘Wonderland Mix’ and ‘Oregon Rainbow’. For Utah gardens grown for seed, Utah State lists ‘Hungarian Bread Seed’, ‘Elka’, ‘Ziar’ and ‘Heirloom Pepperbox’.

Common problems

• Aphids: black bean aphids cluster on buds just before bloom and can spread viruses. Knock them off with a strong spray of water or use insecticidal soap.
• Downy and powdery mildew: favored by crowding and wet foliage. Thin properly and avoid overhead watering.
• Slugs and snails: they eat seedlings in moist spring weather. Traps and baits work well.
• Root and crown rot: caused by soggy soil. Move the planting to a better-drained bed.
• Plants that collapse after transplanting: sow directly instead.