Trifolium incarnatum
Crimson clover
Common names: Italian clover
At a glance
- Light
- Full sun
- Lifespan
- Annual
- Hardiness
- Cold damage below −12 °C
- Water need
- Medium
Photo: CC BY-SA 3.0 · Source
Description
Crimson clover is a nitrogen-fixing cover crop with striking carmine-red flower heads that attract bees and bumblebees in May and June. Through its root nodules of nitrogen-fixing bacteria, it enriches the soil with atmospheric nitrogen and is well suited as a preparatory crop for heavy feeders, but not for other legumes.
Care instructions
Sow crimson clover in April or May, or as a fall sowing in August or September, directly into the bed and rake it in flat. Keep the seedbed evenly moist until germination. The fall sowing will overwinter in mild locations and flower the following May. Cut or roll the plant at flowering and incorporate it flat into the soil, this releases the bound nitrogen to benefit the succeeding crop.
The care notes were machine-translated from German.
Garden year
SowingApr–May, Aug–Sep
Germination
- Soil temperature
- from 5 °C, ideally 18 °C
- Days to sprout
- 5 to 10 days
- Light
- Sprouts in light or dark
- Sowing depth
- 1 cm
- How to start
- Sow straight into the bed
Soil & site
Soil pH
Soil type
sandy, loamy, well-drained, lime-loving
Crimson clover likes loose, free-draining, light to medium-heavy soils. It tolerates waterlogging and heavy, compacted clay soils poorly. It is undemanding about pH: slightly acidic to neutral soils (roughly 5.5 to 7.0) are ideal, so it tolerates lime but is not a lime-lover.
Feeding
Light feeder
Months
Mar–Apr
As a legume, crimson clover fixes atmospheric nitrogen from the air via root nodules; an additional nitrogen feed is unnecessary and even inhibits the nodule bacteria. On depleted soils, work a little ripe compost in shallowly before sowing in spring. As a green manure, you mow or hoe off the biomass before flowering and work it in. That way, the fixed nitrogen becomes available to the following crop.
Overwintering
Sow crimson clover as a winter green manure in late summer, by mid-September at the latest, so that it forms a strong rosette before the frost; only well-developed young plants survive the winter. It stays in the ground and survives frosts down to about -10 °C; in frost without snow cover or in harsh sites, cover the stand thinly with straw or horticultural fleece. In spring, cut it down and work it in; as an annual, it is not stored, but sown again in autumn.
Propagation
Methods
- From seed
Propagate crimson clover by direct sowing only. Other methods make no sense with this annual to biennial species. The best time is in spring from the end of March/April, when the soil is frost-free and sufficiently warm (around 10 to 12 °C). A second sowing opportunity comes in late summer from mid-August to mid-September; the stand then overwinters and flowers the following spring. Broadcast the seeds onto well-loosened soil and rake them in about 1 to 2 cm deep, then press down lightly. Choose a warm, sunny spot with free-draining soil: sandy loams suit it well, the clover avoids heavy or waterlogged soils, and chalky soil is tolerated well. As a legume, it copes with rather nutrient-poor soils and fixes nitrogen itself. With enough moisture, germination takes only about 8 to 15 days. After flowering, small pods with seeds form, which you can collect for the next season and keep in a dark, cool and dry place. You make the best use of the nitrogen gain if you mulch the stand or work it in shortly before or shortly after full bloom.
Companion planting
Good neighbors
cabbage family (Brassicaceae)
particularly well establishedLeguminous plants collect nitrogen in the soil, from which Brassicaceae benefit as heavy feeders.
For example White cabbageKohlrabiRadishKalebroccolicauliflower and 41 more species in the catalogue
Source: classic companion planting (DACH-Gartenpraxis)
carrot family (Apiaceae)
Peas and beans provide carrot and celery with nitrogen and grow as shallow-rooted plants without competition next to each other.
For example CeleriacDillParsleyFlorence fennelCorianderCelery (Stalk Celery) and 20 more species in the catalogue
Source: classic companion planting (DACH-Gartenpraxis)
Rather not
amaryllis family (Amaryllidaceae)
particularly well establishedAllium species inhibit the nitrogen‑fixing rhizobia of legumes through their root exudates, which slows their growth.
For example GarlicOnionLeekChivesWild daffodilRocambole and 12 more species in the catalogue
Source: basic crop‑rotation rule
Companion planting is partly traditional gardening lore. Where the reason is known, it is given.
Some of these explanations were machine-translated.
For your garden
Grow Crimson clover yourself
Gartenkern tells you when frost is coming, when to sow and when to harvest, for your location.
Free, no time limit
Notes from real gardens
What other gardeners have written down about this variety, anonymous and voluntary.
No notes shared yet. Will you be the first to write one down?