Texas Bluebonnets are legendary for their bright blue color and beauty. They will actually grow throughout the Southern United States, however. You can develop and maintain your own patch of bluebonnets with a little work. It takes two to three years to develop a good stand of bluebonnets. At that point, they become self seeding and will come back every year.
Bluebonnets are planted from seed. They do not transplant well. If you are interspersing the bluebonnets into an already established meadow, mow the meadow as short as possible and remove the thatch and grass clippings. Plant bluebonnets in October or November, preferably early October. They require full sun to thrive. You broadcast sow the seeds at a rate of 10 to 12 pounds an acre. An ounce will cover 200 feet. If you are impatient and want your stand of bluebonnets to appear quickly, you can seed at the rate of 20 to 30 pounds of seeds per acre.
The best way to broadcast the seed is to mix it with sand or some other inert substance to make it easier to handle. Use one part seed to four parts sand. Walk with a hand spreader cranking the spreader to distribute the seed. Then walk the area again in a direction perpendicular to the first way you walked. This distributes the seed the most evenly.
Bluebonnet seeds are tough. The first year, you will not get a very good stand. If you continue to plant bluebonnets each year, you will get an optimal stand in two to three years. At this point the plants will reseed themselves provided you do not mow them before the seed pods turn brown and burst. July 15th is generally the best time for a first mowing, if you must mow.
You can improve your germination rates the first and second year by scarification of the seeds. This simply means scratching the seed coating to make it easier for it to germinate. You can use a knife, sandpaper, or a similar substance to thin the coating for better germination. This may not be practical if you are planting a large area due to the labor intense nature of the process.
Like all legumes, bluebonnets have nitrogen fixing bacteria that help them grow and put nitrogen back into the soil. In most cases, it is not necessary to inoculate the seed before sowing. However, if you can find some inoculate of the species Rhizobium you can wet the seeds slightly and roll them or mix them with the inoculants. Inoculants of other species commonly sold for peas and beans do not help. Once the seeds have been inoculated they need to be planted that day.
Once you have planted your bluebonnet seeds, roll or otherwise press them into the soil. Do not bury them as they need light to germinate, but insure good soil contact. Then water the seed in. Occasionally water the seeds and plants if the fall rains are sparse. Do not overwater. Bluebonnets do not like wet soil, only moist soil.
Bluebonnets do not generally require fertilization. In fact, they are famous for refusing to grow when fussed over . Other than occasionally watering them, you should leave them alone. They will grow in the fall and then go dormant for the winter. In mid-March, the blooms start and usually peak in mid-April. The exact dates depend on weather conditions such as spring rains.