How to Grow Skirret USA

By the SoilCommander Editorial Team, under the guidance of Nitin Sharma, Co-Founder · · How we check our facts

On this page
  1. Skirret (Sium sisarum)
  2. Soil & Growing Conditions
  3. Growth Stages
  4. Quick Facts
  5. At a Glance
  6. Harvest & Storage
  7. Pests
  8. Skirret, the Sweet-Rooted Perennial the Tudors Grew
  9. Plan your Skirret planting
  10. Growing Skirret in another region
  11. Sources

Skirret (Sium sisarum) — herbaceous perennial.

Unlike an annual crop, the work here is front-loaded into establishment: get the planting and the site right and the same plants crop for several seasons.

Core growing advice on this page is checked against named horticultural sources — see References.

Skirret (Sium sisarum)

A handful of freshly lifted skirret roots — “Sium sisarum tubers in may” by Eric Toensmeier is licensed under CC BY-SA 3.0.

Also known as: crummock · 4 sources cited · Verified

Soil & Growing Conditions

A skirret plant beside a botanical label reading Sium sisarum — “Sium sisarum (skirret) observation” by edouard-brulhart is licensed under CC0. Source: iNaturalist
“Sium sisarum (skirret) observation” by edouard-brulhart is licensed under CC0. Source: iNaturalist.

Water: moist but well-drained; water during dry spells if roots are to be harvested (RHS)

Growth Stages

A tall skirret plant in white umbel flower against the sky — “Sium sisarum (skirret) observation” by Татьяна Горбушина is licensed under CC0. Source: iNaturalist
“Sium sisarum (skirret) observation” by Татьяна Горбушина is licensed under CC0. Source: iNaturalist.
Stage BBCH Notes
Sowing/planting 0 Grow from seed sown after all danger of frost, or from a purchased crown/root offset for a head start; can also start indoors 8 weeks before the last frost (PITH + VIGOR).
Root and foliage growth 3 Grows 3-4ft tall with large, glossy, dark green, compound pinnate leaves; harvest follows 6-8 months after planting (PITH + VIGOR).
Flowering 6 Delicate white flower umbels appear in summer, also giving the plant ornamental value (RHS).
Dormant-season harvest and division 8 Lift and divide clumps when dormant, November to March, harvesting some roots and replanting sections for continued growth (RHS).

Quick Facts

A handful of freshly lifted skirret roots — “Sium sisarum tubers in may” by Eric Toensmeier is licensed under CC BY-SA 3.0.
“Sium sisarum tubers in may” by Eric Toensmeier is licensed under CC BY-SA 3.0.
Factor Value
Soil texture chalk, clay, loam or sand, deep and fertile (RHS)
Drainage well-drained
Lifecycle herbaceous perennial
Edible parts root

At a Glance

A tall skirret plant in white umbel flower against the sky — “Sium sisarum (skirret) observation” by Татьяна Горбушина is licensed under CC0. Source: iNaturalist
“Sium sisarum (skirret) observation” by Татьяна Горбушина is licensed under CC0. Source: iNaturalist.
Sium sisarum Skirret Stem and bulb nematode Voles PESTS

Harvest & Storage

A handful of freshly lifted skirret roots — “Sium sisarum tubers in may” by Eric Toensmeier is licensed under CC BY-SA 3.0.
“Sium sisarum tubers in may” by Eric Toensmeier is licensed under CC BY-SA 3.0.

When to pick: Lift and divide clumps when dormant, between November and March; white roots taste like sweet carrots and parsnips, harvested for culinary use while some sections are replanted for continued growth (RHS).

Pests

Pinnate skirret foliage growing at ground level — “Sium sisarum (skirret) observation” by Татьяна Горбушина is licensed under CC0. Source: iNaturalist
“Sium sisarum (skirret) observation” by Татьяна Горбушина is licensed under CC0. Source: iNaturalist.
Stem and bulb nematode
moderate

Ditylenchus dipsaci

RHS names this directly: susceptible to stem and bulb eelworm.

Voles
low

Microtus spp. / Arvicola spp.

RHS names this directly: voles may eat the roots.

Plan your Skirret planting

When to sow and plant Skirret depends on your own frost dates. Check the USA vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Skirret in another region

Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.

Sources

The full list of 4 sources behind this guide (Cultivariable, PITH + VIGOR, Plants For A Future (PFAF) and others) is in the references of our UK guide to skirret; they describe the plant itself, which is the same wherever it grows.

Plan next season before the problems start

Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.

Get the USA Garden Planner →

Instant PDF download · Written for US growing conditions

SoilCommander Editorial Team — under the guidance of Nitin Sharma, Co-Founder

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing. How we check our facts.

How this guide is put together

The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against USDA hardiness-zone and frost-date data, with Cooperative Extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.

Vegetable Growing Guides USA

Crops With the Same Problems

Last verified 2026-09-02

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