Blooms All Year Long?
A typical inquiry about this topic goes something like this: What can I plant that will bloom throughout most of the year, does not require water, is fire retardant, and that the deer won't eat. The answer doesn't come from seed! If such a flower exists, I am not aware of it unless it is plastic!
All seed requires some water in order to grow. How much, how often and when usually depend on the type of seed and the time of year that it was planted (see last month's issue on "Exactly How Much Water Do My Flowers Require.")
Most native plants have deep roots. These roots go down to where the water is and provide the plants with sufficient moisture throughout most of the year once they are established. Perennials spend the first year in establishing that feeding system. While the frivolous annuals are busy making blooms and more seed for the following year, perennials are busy sending down deep tap roots to where the moisture level will provide them the assurance of survival for years to come. I have personally traced some perennial taproots as far as 26 feet! I would imagine that some even exceed that!
Plants survive as long as they have moisture. One reason we strongly advocate fall planting of wildflower seed is because they are more able to establish a deep root system in the early spring while the soil is yet moist even wet in many instances. The taproot goes down as the soil moisture recedes, always staying a little ahead of it. This is true largely of perennials. Usually there is enough soil moisture for annuals to germinate, bloom and set seed for the following season.
If you have planted at a time other than the fall, that's ok. You just need to remember that you will need to supply ample water throughout the late spring and summer months, especially if you want your wildflowers to continue blooming. They stop blooming for two reasons. Either they run out of soil moisture or they freeze. Running out of soil moisture is natural, especially for annuals, as they do not have the same deep root system that their perennial cousins do.
So, if you want to prolong the bloom, make sure the plants have soil moisture.
Another hint, especially helpful on prolonging perennial blooms is to cut back the old blooms. What you are doing to the plant is eliminating the "offspring" and it will shoot additional blooms, trying to set seed for the following year. This works especially well on composite or "daisy-like" flowers.