Mature size & growth rate

How big does Black Medick (Medicago lupulina) get?

Also called Black Medick, Black Medic, Hop Clover, Nonesuch, Yellow Trefoil.

More about black medick

About Black Medick

Medicago lupulina · also called Black Medick, Black Medic · flowering

Medicago lupulina is a low-growing annual or short-lived perennial legume native to grasslands, roadsides, and disturbed ground across Europe, Asia, and northern Africa, widely naturalised in North America and Australasia. It thrives in full sun on poor to moderately fertile, well-drained soils and, as a legume, fixes atmospheric nitrogen through root nodules — so avoid nitrogen-rich fertilisers. The tiny yellow clover-like flowers turn into distinctive black coiled seed pods that give the plant its common name. It is not considered toxic to cats or dogs.

Mature size: 10–50 cm tall, spreading 20–40 cm wide.

Watch for — Aphid infestation: Black bean aphid (Aphis fabae) and pea aphid (Acyrthosiphon pisum) can colonise soft new growth; natural predators usually control populations in wildflower settings — intervene with insecticidal soap only on serious infestations.

Indoor size vs how big it gets in the wild

Black Medick reaches its full size within one growing season — there is no "long-term" size, just how big it gets before you harvest or it dies back. Indoors and in a pot, expect 10–50 cm tall, spreading 20–40 cm wide.. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

It sizes up fast and once, racing from seedling to full size in a single season; after cropping it is finished, so size is a within-season question.

Growth rate and years to mature

Black Medick is a moderate grower. Realistically, expect a single growing season — it reaches full size in one year, then is done. Its feeding profile backs this up: do not fertilise — this nitrogen-fixing legume performs best on poor soils; added nitrogen suppresses nodule activity and encourages weedy competition.

Want this turned into the right next pot at the right moment? The pot size calculator and the black medick repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast black medick grows.

How to keep black medick smaller

You are not stuck with the maximum size. For black medick specifically, these are the levers, in order of impact:

Choose a compact or dwarf variety of black medick from the start — that is the most reliable size control for an annual.
Grow it in a smaller container to naturally limit how large it gets.
For some crops, pinching or pruning the growing tips keeps the plant shorter and bushier.
Sow a little later or space plants closer if you specifically want smaller individual plants.

How to grow black medick bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for black medick the accelerators are:

Full sun, warm soil and steady water are what drive a crop to full size fastest.
Sow at the right time for your zone so it gets the whole season to size up.
Feed appropriately for the crop and never let it check (stall) from drought or cold.

Light is almost always the ceiling. The black medick light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When black medick outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for black medick:

It sprawls beyond its bed or container before harvest — usually a spacing or support issue.
It flops or needs staking once it hits full height.
Once it has fruited or bolted, it is at its final size for good — the next plant is a new sowing.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the black medick repotting guide. If you want more of this plant instead of a bigger one, the black medick propagation guide turns prunings into new plants.

Black Medick size — frequently asked questions

How big does black medick get?

Black Medick reaches 10–50 cm tall, spreading 20–40 cm wide. when grown indoors. It sizes up fast and once, racing from seedling to full size in a single season; after cropping it is finished, so size is a within-season question.

Is black medick slow or fast growing?

Black Medick is a moderate grower. Expect a single growing season — it reaches full size in one year, then is done. Black Medick reaches its full size within one growing season — there is no "long-term" size, just how big it gets before you harvest or it dies back.

How long does black medick take to reach full size?

Roughly a single growing season — it reaches full size in one year, then is done. Light, pot size and feeding move that timeline more than anything else.

How do I keep black medick smaller?

Choose a compact or dwarf variety of black medick from the start — that is the most reliable size control for an annual. Grow it in a smaller container to naturally limit how large it gets. For some crops, pinching or pruning the growing tips keeps the plant shorter and bushier. Sow a little later or space plants closer if you specifically want smaller individual plants.

How can I make black medick grow bigger or faster?

Full sun, warm soil and steady water are what drive a crop to full size fastest. Sow at the right time for your zone so it gets the whole season to size up. Feed appropriately for the crop and never let it check (stall) from drought or cold.