Horned mason bee
Osmia cornuta
Role in the garden
One of the very first spring pollinators, emerging as early as February in a mild climate. Precious for early-flowering fruit trees, such as the almond, which it can pollinate (Bosch, 1994), the plum and the peach.
Activity period
February to April
How to attract / manage it
The female is recognisable by her two small horns on the head. Solitary but makes clustered nests (“aggregations”).
Practical guide
Where to find them
In orchards in flower very early in spring. The female is red-black with two characteristic frontal horns; the male is smaller, without horns. Nests in pre-existing cavities (hollow stems, wall holes, insect hotels).
Prevention
An insect hotel set up the previous autumn (mason bees shelter there as cocoons over winter). Preserve old walls, dead trunks in the orchard. Early flowering essential (goat willow, blackthorn).
Sources
- Bosch, J. (1994). Improvement of field management of Osmia cornuta (Latreille) (Hymenoptera, Megachilidae) to pollinate almond. Apidologie, 25(1), 71-83.
Favourite plants / resources
Related plant entries
Cherry tree
A high layer (6-12 m). Early flowering in April, a frost risk to anticipate. Cross-pollination by mason bees and bees. The sweet-cherry tree (bigarreau) needs a compatible pollinator; the sour-cherry tree (morello) is self-fertile.
Plum tree
A high layer (4-8 m), sometimes suckering on its own roots. Flowering March-April, precious for early-emerging horned mason bees. Several species: European plum (Prunus domestica, quetsche, mirabelle, greengage), Japanese plum (P. salicina, Methley), wild blackthorn (P. spinosa).
Peach tree
Prone to peach leaf curl (Taphrina deformans), preventive sprays of horsetail decoction from February. Very early flowering (March) threatened by late frosts: prefer sheltered south-east exposures. Lives 15-20 years (relatively short for a fruit tree).
Blackthorn (sloe)
A thorny shrub with vigorous suckering, blackthorn forms dense, impenetrable hedges that protect the garden and shelter abundant wildlife (nesting, insect overwintering). Its early white flowering, from March before the leaves, offers one of the first sources of nectar and pollen of the year for bees coming out of overwintering.