Sow native thistle in fall on bare soil, or cold-stratify stored seed in the refrigerator. Cover only as that species needs — field thistle gets a light covering, yellow thistle needs light.
Sow native thistle in fall, or cold-stratify stored seed
| Factor | Recommended | Avoid |
|---|---|---|
| When | Sow outdoors from early fall into late winter | Do not wait for a warm indoor tray if you can use winter weather |
| Field thistle | Bare soil; cover no more than a quarter inch | Do not bury the seed an inch deep |
| Swamp thistle | Dormant surface sow, or about 30 days cold-moist | Do not skip moisture on stored seed and then expect a full tray |
| Yellow thistle | Press seed onto the surface; it needs light | Do not cover it with soil |
The simplest start is a fall sowing on a weed-free spot. Winter cold does the work that a refrigerator does for stored seed. [1] field thistle can be sown from late fall into early spring on bare soil, then covered no more than a quarter inch. [2] swamp thistle is a dormant sow on the surface, or a thirty-day cold-moist spell if you start in a bag of damp sand. [3] cobwebby thistle often germinates from a fall sowing; seed that has sat in storage may need 60 to 90 days of cold-moist treatment. bristle thistle needs light, so you press it in and leave it visible.
When do I sow native thistle?
Sow outdoors in fall or winter. If you missed that window, cold-stratify stored seed, then sow in spring.
How to sow native thistle
Clear competing grass, then sow. Keep the surface moist until seedlings show. Move taprooted seedlings while they are still small.
- Pick a sunny, weed-free patch that matches the kind — draining ground for field and cobwebby thistle, wet ground for swamp thistle.
- For field thistle, sow on the surface and rake or spread no more than a quarter inch of soil over the seed.
- For swamp thistle, press seed onto the surface in late fall, or refrigerate damp seed for about thirty days, then sow.
- For bristle thistle, press seed onto moist mix and do not cover it. Keep the surface moist until it sprouts. [4]
- If you start in pots, use a deep cell. The taproot runs fast. Transplant in the first year, in spring or fall, before the root circles the pot.
Do I cover native thistle seed?
Field thistle gets a light covering, no more than a quarter inch. Bristle thistle needs light, so do not cover it. Swamp thistle is a surface sow.
What fails a sowing
- Burying yellow thistle. Light never reaches it, and the tray stays empty.
- Sowing into thick turf. Clear competing grass first, or the rosette never gets a start.
- Leaving a seedling in a shallow plug until the taproot coils. Use a deep cell and plant out the first year.
The moist crimson border perennial is How to Grow Plume Thistle. Site and Canada thistle ID live on How to Grow Native Thistle.
If the packet is still in a drawer, sow it on bare soil this fall, or start a damp-sand bag in the refrigerator this week.
FAQ
Can I grow ‘Atropurpureum’ from seed?
You can try, but the garden clump is usually increased by division. Named crimson plants are more reliable from a nursery division than from a seed packet.
How long until native thistle flowers?
Plan on a rosette the first year and bloom the second summer. A plant that goes into winter at a good size usually flowers the next year.
Do I need a refrigerator?
Not if you sow outdoors in fall. Use the fridge for stored seed, or for a spring start: damp sand, about thirty days for swamp thistle, longer for old western seed.
Can I collect my own seed?
Yes. Clip heads when the fluff just shows, dry them in a paper bag, and sow that fall. Goldfinches and wind empty a head fast, so check daily.
Related guides
Recommended plants
References
- [1] Klamath-Siskiyou Native Seeds -
https://klamathsiskiyouseeds.com/2021/12/29/growing-native-thistles/ - [2] USDA NRCS -
https://plants.sc.egov.usda.gov/DocumentLibrary/factsheet/pdf/fs_cidi.pdf - [3] Prairie Moon Nursery -
https://www.prairiemoon.com/cirsium-muticum-swamp-thistle - [4] NC State Extension Gardener -
https://plants.ces.ncsu.edu/plants/cirsium-horridulum/
This note is part of Cirsium Guides.
More notes on making another plant live in Propagating Guides.
Updated: Reviewed by Bosquelle Editors