How to Plant a Dr. Alexander Fleming Peony

When and where to plant

Dr. Alexander Fleming Peony is hardy in zones 3 through 8 and needs a real winter to bloom well. The plant requires roughly 400 hours of temperatures below 40°F each winter to set flower buds for the following spring, which is why peonies struggle south of zone 8.

The best planting window is early fall, about six weeks before your ground freezes hard, usually mid-September into October across most of the country. Fall planting lets the roots establish before winter dormancy, setting up strong growth the following spring. Spring planting from a potted nursery plant works too but pushes the first real bloom display back another full year.

Pick a site with at least six hours of direct sun. Less light means floppy stems and few flowers. The soil needs to drain well, since peonies rot quickly in standing water. Heavy clay should be amended with compost or the plant set on a slight mound. Space plants three feet apart and keep them well away from competing tree and shrub roots, which can starve a peony of water and nutrients for decades to come.

Planting a bareroot tuber

The single most important rule for Dr. Alexander Fleming Peony is planting depth. The pink growth buds on the tuber, called eyes, must sit just one to two inches below the soil surface in cold zones 3 through 5, and barely covered in warmer zones 6 through 8. Tubers buried any deeper produce leaves but rarely flower, sometimes for the lifetime of the plant.

1. 1
   Inspect the bareroot tuber When the bareroot arrives, look for three to five pink or red growth buds, the eyes, on top of a firm fleshy root mass. A healthy peony root is heavy for its size with no soft spots, mold, or mushy patches. Soak the roots in plain water for one to two hours before planting if they look dry and shriveled.
2. 2
   Dig a wide planting hole Dig a hole about 18 inches across and 12 to 15 inches deep, much wider than the root mass itself. Mix the removed soil with two to three shovelfuls of compost and a handful of bone meal for slow-release phosphorus. A wide loose planting area gives the new roots room to spread without fighting compacted ground.
3. 3
   Set the eyes at the correct depth This is the step that makes or breaks years of blooming. Hold the tuber so the eyes face up and use a ruler to confirm they sit one to two inches below the finished soil line in zones 3 through 5, or just barely covered with a thin layer of soil in zones 6 through 8. If the hole is too deep, backfill with amended soil and check again with the ruler before letting go.
4. 4
   Backfill and water in Gently fill in around and over the tuber with the amended soil, firming lightly with your hands to remove air pockets without packing the soil hard. Water deeply with about a gallon to settle the soil around the roots. Check the depth one more time after watering, since soil sometimes settles below where you set it and exposes the crown.
5. 5
   Mulch thinly for winter only Add a one to two inch layer of light mulch like straw or shredded leaves over the planting area to protect against winter heaving in the first year. Pull this mulch back to about an inch in early spring as soon as the soil thaws, so the emerging shoots are not delayed by cold wet cover. Never mulch over the crown in subsequent years, which traps heat and reduces flowering.

Planting a container-grown peony

A nursery container peony works for spring planting when bareroots are no longer available. Container plants have less transplant shock than bareroots but typically need an extra year to settle in before strong blooming begins. The same depth rule applies, since the eyes still need to sit near the surface to flower well.

1. 1
   Pick a cool planting day Plant in spring once nighttime lows stay above 40°F, usually April or early May across most of the country. A cool overcast day reduces transplant stress on freshly disturbed roots. Avoid planting through summer heat, which often pushes a spring-planted peony into a full year of stalled growth.
2. 2
   Dig the hole twice as wide Measure the container, then dig a hole twice as wide and the same depth as the pot. A wide hole lets the new roots spread laterally into native soil instead of circling. Mix the removed soil with compost and a handful of bone meal before backfilling.
3. 3
   Find the eyes and set the depth Slide the plant out of the container and look for the pink or red growth buds at the base of the stems where they meet the root mass. Position the plant so these eyes sit one to two inches below your finished soil line in cold zones, or just barely covered in warm zones. The original pot soil line is often too deep, so adjust upward as needed.
4. 4
   Backfill, water in, and mulch thinly Backfill the hole with the amended soil, firming gently around the root ball with your hands. Water with one to two gallons to settle the soil, then add a one to two inch layer of light mulch around the plant but not directly over the crown. Mulch on the crown traps heat and moisture and is the most common reason a healthy-looking peony fails to bloom.

The first year

The first year for a newly planted peony is almost entirely an underground story. The plant is building the thick fleshy root system that will support a hundred years of flowering, and most of its energy goes there instead of into top growth. Light flowering or no flowering at all in year one is completely normal and expected.

The most common new-grower mistake is reading slow above-ground growth as a sign of trouble and either fertilizing heavily or moving the plant to a new spot. Both reset the establishment clock. Peonies dislike being moved and a relocated plant often takes another two to three years to recover. Stick with the original site and let the roots do their work.

Healthy first-year growth from a fall-planted bareroot looks like a small flush of red shoots emerging in spring, expanding to a low mound of foliage by early summer. From a spring-planted container, expect the existing foliage to hold through summer with little new growth and the plant to die back normally in fall.

What can go wrong

1. No flowers in year two or three

   Planted too deep is the most common cause. Peonies form flower buds based on the temperature swings their crown experiences, and a crown buried more than two inches below the soil never gets the cues it needs. Carefully dig the plant in early fall, reset it with the eyes one to two inches below the soil in cold zones or barely covered in warm zones, and expect another year or two before blooming starts.

2. Buds form then turn brown and shrivel

   This is called bud blast and is usually caused by a late frost or by sudden swings between cool wet weather and dry heat as buds develop. The plant itself is fine. Snip off the failed buds, keep the foliage healthy through summer, and most peonies set normal buds again the following spring with no intervention needed.

3. Gray fuzzy mold on stems and buds

   This is botrytis blight, a fungal disease that thrives in cool damp spring weather. Cut out affected stems at ground level and bag them in the trash to remove the spores from your garden. Improve air circulation around the plant by removing nearby weeds and check that fall cleanup in past years removed all the old foliage, which carries spores into the next season.

4. Stems flop over once buds get heavy

   The huge double flowers of this peony are heavy and bend stems to the ground after rain. The plant itself is fine but the blooms can mud out. Install a grow-through metal hoop or peony ring over the plant in early spring before the foliage is more than six inches tall, so the stems grow up through the support naturally instead of being tied to it later.

5. Ants crawling all over the buds

   Ants feeding on the sticky sugar coating that peony buds produce are harmless and do not damage the flowers. Some growers think ants are needed for blooming but they are not. If you cut flowers for inside, hold the stems upside down and gently shake or rinse the buds in a bowl of water to dislodge the ants before bringing them in.

6. Soft mushy tuber in spring

   Soggy ground over winter caused the tuber to rot. Heavy clay, low spots that collect runoff, and recent overwatering are the usual culprits. Lift the plant, cut away any rotten sections back to firm white root tissue with a clean knife, dust the cuts with cinnamon or garden sulfur, and replant on a mound of well-drained amended soil. Do not replant in the same low spot.

7. Crown pushed up out of the soil over winter

   Freeze and thaw cycles in the first winter can heave a new tuber upward, leaving the crown exposed. Push the crown gently back down to the correct depth as soon as the ground thaws in spring, and add a thin layer of soil over any exposed roots. A one to two inch layer of straw or shredded leaf mulch the following fall prevents this from happening again.

8. Foliage browns and dies back in late summer

   A complete dieback by August is unusual and often points to drought stress, root rot from wet soil, or foliar disease catching the plant in a weak first season. Check the soil moisture an inch down before watering, water deeply once a week during dry stretches in the first year, and clean up any fallen leaves to slow the spread of fungal spores. The plant should return normally the following spring from the underground roots.