Another reliable plant in our front garden is the perennial Blue False Indigo, Baptisia australis, a member of the family Fabaceae (legumes) that contains other garden plants such as beans, sweet peas, lupines and the shrubby caraganas. Blue False Indigo grows best in gritty well-drained soil, but it also does well our clay-based Edmonton earth. It can be slow to establish, but is long-lived and will eventually grow to about 90 to 120 cm tall (3 to 4 feet) and wide. The stems begin branching half-way up and have grey-green foliage with trifoliate leaves. The flower spikes are tipped with upright terminal racemes with the pale blue to deep violet pea-like, bisexual flowers about 2.5 cm (1 inch) long. It thrives in full sun and is tolerant of dry conditions.
B. australis flowers in early summer for about two weeks. The sexual parts of the flowers are enclosed by the two lower petals (called a keel), with the pollen-bearing anthers in close contact with the stigma, so it can be self-pollinating. However, the flower design still allows for insect pollination in a very selective way.
The petals of the Blue False Indigo flower are arranged in a classic pea-flower shape. There is a large upper petal called the banner (sometimes called the standard) with a petal called the wing on either side. The two lower petals that form the keel are fused on the bottom edge and contain the stamens and pistil. The nectar lies at the base of the stamens, which are unreachable by most insects. Most, but not all–bees of a certain weight and/or persistence can find a way to get at the riches of nectar and pollen that are hidden deep within the flower.
(All images taken in our front garden in Edmonton, Alberta between June 24 and July 3, 2014)