Tagasaste or tree lucerne is a perennial forage shrub or small tree that grows well in mild, temperate climates. It can provide good feed for farm livestock maintenance and for wool growth, and provides shelter from chilling winds. It also supplies good firewood where that is needed.
Tree lucerne grows up to 5 m high, and almost the same across. Its very deep roots grow up to 8 m long, and above ground it has long, drooping branches with dull, blue-green trifoliate leaves, hence its common name, tree lucerne. White legume-like flowers develop in late winter to early spring, and later black seedpods develop in clusters, each up to 5 cm long. It prefers deep, free draining soils and doesn’t like being waterlogged. Annual yields of up to 10 tonnes per hectare of edible leaf and fine stem are achievable.
Tree lucerne is usually established from rooted young plants. Stands can also be grown from collected seed but this is usually low in germination. Dropping the seed into boiling water and immediately removing it will break its dormancy – but remember that it needs inoculating, though sowing in local topsoil seems to work as it resows itself in some New Zealand regions.
Any pasture growing between the tree lucerne rows helps to prevent soil erosion while the plants establish. Plant rows 6-l0 m apart with plants every 2 m within a row. Corners of paddocks can be planted in tree lucerne for browsing.
Plants can be safely grazed or trimmed at a year after sowing or when 25 cm high, to encourage a multi-stemmed plant to develop that tolerates grazing. Insect pests can attack stands during the first year, so check them weekly and spray with pesticide as necessary. Young plants are also very acceptable to wild animals such as rabbits and hares, so using tree guards, protective fencing and repellents will help during establishment. Inter-row cropping or haymaking during the first two years also keeps the pasture understorey under control.