When we visited the Ansin Tract Conservation Area on 3-30-2019, we saw false indigo (Amorpha fruticosa) growing along the St. Sebastian River and in other moist places. This plant goes by variety of common names: Bastard false indigo, bastard indigo, leadplant, and desert false indigo.
This shrubby member of the pea family, Fabaceae, can grow to be 20′ tall in Florida and often is multi-trunked. It is very variable in morphology, but its racemes of striking spring flowers are unmistakeable.
Each flower has one purple petal and 10 stamens with golden anthers. The genus name, Amorpha, comes from the Greek word armophos, which means without form, and some folks say that it refers to the amorphous nature of the single-petaled flowers. The species name, fruticosa, means shrubby.
The inflorescence is indeterminate: Flowering begins at the bottom of the spike and progresses to the top. This process takes about 2 weeks.
Its alternate leaves are odd-pinnate in arrangement with 9 to 31 leaflets.
The leaflets are opposite, dotted with glands, and tipped with soft spines.
This plant is native to all of the U.S. and much of eastern Canada. Though native, it is regarded as invasive in Maine and Oregon. It is deciduous in the northern parts of its range.
This plant is quite adaptable, and, though it prefers moist places, false indigo can be found growing on the return path in the mesic hammock at the Oslo Riverfront Conservation Area. With its dramatic spikes of purple flowers, false indigo can be an excellent addition in your landscape for beauty, pollinators, and as a larval host plant for the silver-spotted skipper (Epargyreus clarus), Southern dogface (Zerene cesonia), and gray hairstreak (Strymon melinus) butterflies.