Lesser Trefoil is an annual weed in the bean family found all over the world in disturbed sites, roadsides, meadows, and lawns. It is a legume so it fixes nitrogen in the soil. This plant is what is commonly used as the inspiration for the Irish Shamrock. Tiny yellow flowers attract bees to their nectar from late spring to early fall. It can be used for animal forage, it will often be seen in lawns where it handles foot traffic and mowing well. Although this plant can cause issues with some plants, (see below), with others it can be beneficial. When grown in an apple orchard the fruits produced can be tastier. The flowers grow in the form of a raceme and sit atop a long stalk. Each raceme will contain 3 to 15 flowers Insects, Diseases, and Other Plant Problems: This plant cannot grow in the shade. It should not be planted near camellias or gooseberries. It harbors a mite that may lead to fruit drop for the gooseberries and premature budding on your camellias. Considered to be invasive in some states.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day)
Soil texture
Clay; Loam (Silt); Sand
Soil pH
Acid (<6.0); Alkaline (>8.0); Neutral (6.0-8.0)
Soil drainage
Good Drainage | Moist
Available space
12 inches-3 feet
NC region
Coastal
Growth rate
Rapid
Maintenance
Medium
Form & Appearance
Habit / form
Ascending
Texture
Medium
Foliage
Deciduous
Leaf color
Green
Leaf type
Compound (Pinnately , Bipinnately, Palmately)
Leaf arrangement
Alternate
Leaf margin
Entire; Serrate
Leaf size
< 1 inch long, < 1 inch wide
Hairs present
No
Leaf detail
2 to 3 leaflets with slightly curved margins.
Flower color
Brown/Copper; Gold/Yellow
Flower form
Head; Raceme
Flower size
< 1 inch
Flower detail
Yellow flowers appear May-October and are self fertile as they have both male and female parts. As they age, they take on a yellowish-brown color. Each flower has 5 petals, while 3 to 15 flowers will bloom on the raceme.
Bloom time
Fall; Spring; Summer
Fruit type
Legume
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Dry does not split open when ripe. Each contains 1 seed that will remain inside the calyx.
Stem detail
The then stem is limp or ascending with few hairs. It can lay along the ground or be erect.
Wildlife & Ecology
Native status
Non-native
Origin
Macronesia, Europe
Wildlife value
This plant supports Clouded Sulfur (Colias philodice) larvae which appear from May to October in the North and from March to November in the South. There are 3 flights in the North and 4 to 5 flights in the South. Adult Clouded Sulfur butterflies feed on flower nectar from many different plants. Flowers are pollinated by bees.
Attracts
Bees; Butterflies; Pollinators
Play value
Attracts Pollinators; Wildlife Larval Host
Food & Medicine
Fruit type
Legume
Landscape Use
Landscape location
Lawn; Meadow
Landscape theme
Butterfly Garden; Pollinator Garden
Design feature
Border
Garden tags
#nectar plant early summer #nectar plant #nectar plant mid-summer #nectar plant late summer #nectar plant early fall #nectar plant late spring #forage #disturbed areas #roadside #butterfly friendly #larval host plant #clouded sulphur butterfly #bee friendly #legume #herbaceous #herbaceous annual #pollinator plant #wildlife friendly #meadow #weedy