Melilotus officinalis
Yellow sweet clover
Common names: Ribbed melilot, Sweet clover
At a glance
- Light
- Full sun
- Spacing
- 30 cm, rows 40 cm
- Lifespan
- Biennial
- Sowing
- Mar, Apr, May, Aug, Sep
- Harvest
- Jun–Aug
- Hardiness
- Hardy down to −15 °C
- Water need
- Low
- Origin
- Native to Germany
Description
Melilotus officinalis is a biennial butterfly‑flowering plant that produces bright yellow flower heads from June to August, attracting bees and bumblebees in large numbers. In home and community gardens it is often used as a green manure: its deep taproot loosens heavy soils, and as a legume it enriches the soil with nitrogen. When dried, the leaves release a characteristic wood‑mint scent of coumarin, which has traditionally been used in herbal pillows and teas for tired legs. However, improper storage or mold growth can convert coumarin into a blood‑thinning substance that is hazardous to animals and humans, so dried sweet clover should be kept dry, mold‑free, and out of reach of small children.
Care instructions
Sweet clover prefers a sunny to partially shaded location with well‑drained, even calcareous soil and tolerates drought well. Sow in a broad spread from mid‑March (week 12) to May; a second sowing in August is possible. Cover seeds lightly with soil. In the first year the plant mainly develops foliage; flowers appear in the second year. After flowering, the plant can be incorporated as green manure or cut back. Regular thinning promotes stronger individual plants and better airflow. Water only during extended dry periods; soggy soil is detrimental to the deep roots.
The care notes were machine-translated from German.
Garden year
SowingMar–May, Aug–Sep
HarvestJun–Aug
Germination
- Soil temperature
- from 8 °C, ideally 18 °C
- Days to sprout
- 7 to 21 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
well-drained, lime-loving, lean, dry
Ribbed melilot loves chalky, well-drained soils and also copes well with lean, dry sites. It does not tolerate waterlogging at all; its deep taproot taps water from deeper layers by itself, even on dried-out ground. On heavy, compacted soils it even loosens the subsoil over time.
Feeding
Light feeder
As a legume, melilot fixes atmospheric nitrogen through its root nodules and largely supplies itself with it. You need no additional feeding; on the contrary, soils that are too rich in nutrients make it grow limp and prone to disease. A thin dose of compost in spring is quite enough as a gentle start.
Overwintering
In the first year, melilot forms only a leaf rosette and survives the winter outdoors without difficulty, with no protection. The taproot makes it robust against frost well below minus 15 degrees. In the second year it shoots strongly in spring, flowers and dies off after the seeds have ripened.
Propagation
Methods
- From seed
Melilot is propagated by seed only, best sown directly outdoors from April to June. The seeds need light to germinate, so just press them down lightly and do not cover them with soil. Because as a biennial it forms only a rosette in the first year, you need patience until flowering in the second year. Once established, it likes to self-seed by itself in suitable spots.
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 CarrotCeleriacDillParsleyFlorence fennelCoriander and 21 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 Yellow sweet clover yourself
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