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Centaurеa ruthеnica (Russian knapweed)
Centaurеa ruthеnica (Russian knapweed) field
Centaurеa ruthеnica (Russian knapweed)

Russian knapweed / star thistle

Centaurеa ruthеnica

Regular price
$8.99
Regular price
Sale price
$8.99
Shipping calculated at checkout.

FALL 2025. Sign up for the waitlist to be notified when available for purchase.

PLEASE KNOW: Plants shipped in early spring are likely to arrive dormant.

Shaggy, creamy-yellow pompom flowers dance on long wiry stems above finely cut ferny-foliage. This rarely encountered perennial is extremely easy to grow in most soil in full sun. Requires good drainage through winter.  

We look forward to posting photos of the gorgeous foliage once our plants grow out a bit more. 

syn. Rhaponticoides ruthenica

Zones: 5 to 8
Family: Asteraceae
Type: Perennial
Height: 36 to 48 in.
Spread: 18 to 24 in.
Exposure: Full sun
Soil Conditions: well-drained, average, dry
Bloom Time: July to September
Bloom Color: pale yellow
Native Range: South Russia to Central Romania

Special Characteristics
  • Deer-resistant
  • See-through plant
image credits

C T JohanssonCC BY 3.0, via Wikimedia Commons
GalinaGouz, via Wikimedia Commons
Igorpsyh, via Wikimedia Commons

Centaurеa ruthеnica (Russian knapweed)
Centaurеa ruthеnica (Russian knapweed) field
Centaurеa ruthеnica (Russian knapweed)

Ordering information

Preorders

You may place your order anytime to reserve plants for spring 2025 shipment. If you place multiple orders, we will combine plants into one box (or as many as needed) and any extra shipping charges will be refunded when we ship.

We will begin shipping plants as soon as plants begin to emerge from dormancy in spring. Woodies will likely begin shipping in April. Perennials will likely begin shipping in May. If ordering multiple varieties, we will hold until all plants are ready to ship together. If you would like to receive plants sooner please reach out.

We will check in with you a week before shipping to make sure you receive your plants at a time that is convenient for you.

Shipping

Live plants ship in spring and fall only. Plants may ship dormant, depending on variety and season. Shipping costs are most reasonable when bundling like size plants.

  • 4-inch: 1-6 plants ship for $15.00 / 7-13 plants ship for $18.00 / 14-30 plants ship for $40.00
  • 1-gal: 1-2 plants ship for $18.00 / 3-4 plants ship for $25.00 / 5-6 plants ship for $40.00
  • trees & shrubs: $27.00-$40.00 each, height dependent
  • seeds: $6.75 or free with orders over $15.00

We regret that we cannot ship internationally or to the following states: AK, AZ, CA, CO, FL, HI, ID, MT, NV, OR, UT, or WA.

Read more about our shipping policies here.

Nursery pick up

Plants can be collected from the nursery Monday through Sunday from 10am-4pm in Spring, Summer, and Fall. We prefer 24 hour notice to get your order together and will email you when ready for collection.

If you place a SPRING 2025 PREORDER, we will contact you in spring when your plants are ready for collection. Woodies will likely become available for collection in April. Perennials will likely become available in May. If ordering multiple varieties, we will hold until all plants are ready to be collected together.

Plant Sizes

We most commonly use the following pot sizes for perennials:

  • 4-inch pot: 3.5" H x 3.5" W x 3.5" D
  • 2-quart pot: 6" H x 5.25" W x 5.25" D
  • 1-gallon pot: 6.87" H x 8" Dia (this is a true one gallon pot, not the smaller 'trade' one gallon pot used by many nurseries)

Check out our illustrated pot size guide here.

Representative trees & shrubs are photographed in their pots and posted on each plant page.

Sustainability

Sustainability is at the heart of what we do at The Old Dairy. We grow all of our plants outdoors without the use of chemicals, fertilizers, carbon fuels, or peat.

Many of our perennials are grown in the ground and dug upon order (this is especially true for larger sizes). This practice allows us to grow stronger, healthier plants using native soil, and ultimately reduces our impact on the environment.

Our open-pollinated seeds are collected from plants in our mother beds, which have never been treated with chemicals or sprays of any kind.

Read all about our sustainable practices here.

garden location coming soongarden location coming soon
garden location coming soongarden location coming soon

view this plant in our garden

Centaurеa ruthеnica |

seedling image

Centaurеa ruthеnica

We are slowly creating a seedling image library to help make weeding easier.
garden location coming soongarden location coming soon
garden location coming soongarden location coming soon