Growing Peonies in the Treasure Valley

Peonies thrive in full sun here in Boise, though they appreciate a touch of afternoon shade during our hottest July/August days of summer. Aim for 6–8 hours of sunlight and choose a spot with good airflow to prevent fungal issues.

Soil Tips for Boise’s High‑Desert Conditions

Our local soils tend to be alkaline and clay‑heavy, so peonies appreciate a little help:

• Mix in Ferti-lome Ultimate Potting Soil to improve drainage

• Avoid low spots where water pools

• Keep the soil slightly acidic to neutral when possible. Use Hi-Yield Iron-Plus to lower the alkalinity of our Treasure Valley soils.

Peonies are tough, but they reward good soil prep with stronger stems and bigger blooms.

Types of Peonies

Tree Peonies

• Shrub‑like, some reaching 5–7 feet

• Huge, silky blooms

• Earlier bloom time and excellent heat tolerance

Herbaceous Peonies

• Classic garden peonies

• 2–3 feet tall, 2–4 feet wide

• Low‑maintenance and extremely hardy

Itoh (Intersectional) Peonies

• Hybrid of tree + herbaceous

• Large flowers, strong stems, long bloom window

• Excellent choice for Boise gardeners wanting reliability + showiness

How to Plant Peonies

Planting Potted Peonies

(Available at Aloha Home & Garden in spring and fall)

1. Dig a hole so the top of the root ball sits level with the soil (herbaceous) or 2 inches below soil level (tree peonies).

2. Loosen any circling roots.

3. Add Ferti-lome Ultimate Potting Soil (Ask for a copy of our “Planting Instructions”. This pamphlet provided detailed instructions on planting most trees, shrubs, perennials and annuals.

4. Spread roots over the mound and backfill.

5. Water deeply.

Planting Bare‑Root Peonies

(Usually planted in fall)

1. Soak roots for a few hours in Ferti-lome Root Stimulator and water and mix according to directions..

2. Dig a hole wide enough for the roots to spread.

3. Set the “eyes” 1–2 inches below the soil surface.

4. Backfill and water well.

5. Water occasionally during the first summer, especially during Boise’s hot, dry spells.

Care & Maintenance

Peonies are wonderfully low‑maintenance plants once established.

• Staking: Herbaceous and tree peonies often need support. Place a peony cage in early spring as shoots emerge.

• Watering: Not thirsty plants, but appreciate water during our hot, long dry periods.

• Airflow: Avoid crowding near shrubs or fences.

• Deadheading: Remove spent blooms to encourage tidiness and sometimes additional flowering.

  

  A group of peonies in bloom

When Peonies Bloom in the Treasure Valley

• Herbaceous peonies: Late May to early June

• Tree peonies: Late spring, often earlier than herbaceous

• Itoh peonies: Extended bloom period — early summer into early fall

Itoh and tree peonies bloom in waves, so not all flowers open at once — a huge bonus for long-lasting color.

When to Cut Back Peonies

• Herbaceous & Itoh: Cut back to 4–6 inches in fall once foliage fades.

• Tree Peonies: Do not cut to the ground. Only shape lightly in spring.

Best Time to Plant Bare-Root Peonies in Boise

Fall is ideal - late September through October - giving roots time to settle-in before winter. Spring planting is possible, but those plants often skip blooming their first year while they establish.

Peonies dislike being moved, so choose your location carefully and plan for the long term.

Bring Peonies Home from Aloha Home & Garden

Whether you’re dreaming of a fragrant herbaceous variety, a dramatic tree peony, or a long‑blooming Itoh hybrid, Aloha Home and Garden has selections perfectly suited for Boise’s climate. Our team is always happy to help you choose the right variety and planting spot.

Happy gardening…

Dennis C.