The Parts of a Bluebonnet

Flowers

• Bluebonnet flowers have a shape like a sweet pea flower, only much smaller. There is a top banner petal, two side wing petals, and a central keel of two fused petals that enclose flower's reproductive parts. The common name comes from the flower's resemblance to an old-fashioned sunbonnet. Texas bluebonnet flowers are deep blue with a white spot at the base of the banner petal. There are also white, lavender, maroon and pink cultivars. The flower buds at the tip of the stalk are white. The impressive floral display is due to the massing of the small flowers, as many as 50 per stalk, along the bluebonnet's stem and to the large number of plants growing closely together.

Fruits and Seeds

• Once a flower is pollinated, the seed pod begins to form. It begins as a small gray-green structure in the middle of the faded flower. As it grows, it develops a shape like an erect pea pod and becomes dull green, turning to brown as the pod dries and hardens around the maturing seeds. There are multiple pods per flower stalk. When ripe, pods split open along the edges, curling back to throw the seeds some distance from the mother plant. The rounded flat seeds have a hard, somewhat mottled, seed coat in shades of brown which contains germination inhibitors. To germinate the seeds, you have to soften the seed coat so water can enter the seed, a process called scarification. You can rub the seeds against sandpaper or put seeds into water, bring the water to a boil, turn off the heat and let them soak overnight. Bluebonnet seeds can remain dormant in the soil for years waiting for just the right conditions to germinate.

Leaves and Stem

• Bluebonnet leaves usually have five lance-shaped light-green leaflets joined together at their bases looking like the spread fingers on a hand. The bottom leaves are largest, with the size decreasing near the flower stalk. The stem of the flower stalk rises from the center of the plant and grows 12 to 24 inches tall. The plant's size depends on the growing conditions during a given year. Years with ample fall and winter rain produce large plants. The life of a bluebonnet plant is short, from fall of one year to May or June of the next year.

Roots

• When the seeds sprout, one part of the sprout grows upward, called the hypocotyl, and turns into the stems, leaves and flowers of the plant. The other part grows downward, the radicle, and gives rise to the root system. Texas bluebonnets have a main taproot and spreading lateral roots growing from it. The taproot anchors the plant and the side roots gather food and moisture. An uprooted bluebonnet might have rounded lumps along the roots. These are nodules containing a nitrogen-fixing bacteria (Rhizobium spp.) which convert atmospheric nitrogen to a form the plant can use.