Blanket flower (Gaillardia) is a popular, resilient perennial or annual known for its daisy-like flowers and long blooming season. This North American native spreads readily, but it is not considered ecologically invasive. Its vigorous growth habit quickly fills out a garden area, leading to dense clumps and numerous “volunteer” plants the following season. The spread is typically contained within a garden bed and is usually aggressive only through a specific reproductive mechanism.
The Primary Ways Blanket Flower Multiplies
The primary way Gaillardia multiplies is through prolific self-seeding, especially in the common perennial hybrids (Gaillardia x grandiflora). Each flower head produces numerous viable seeds equipped with a pappus, a tuft of tiny hairs that aids in wind dispersal. These seeds often drop close to the parent plant, resulting in a dense cluster of new seedlings, or they can be carried short distances to germinate elsewhere.
Annual varieties, such as Gaillardia pulchella, are known for abundant self-seeding, ensuring the plant’s return year after year. If spent flowers are allowed to mature and drop their seeds, the resulting volunteer seedlings can be numerous enough to crowd out neighboring plants.
Another method of multiplication is vegetative spread through the root system, though this is slow and manageable in most cultivated varieties. Perennial types, like Gaillardia aristata, are clump-forming, meaning they expand gradually outward but stay in one place. This slow lateral spread is not aggressive and does not involve the extensive, running rhizomes found in aggressive groundcovers.
Techniques for Controlling Aggressive Self-Seeding
Controlling the spread of blanket flower primarily involves managing the abundant seed production to prevent the influx of volunteer seedlings. The most effective technique is deadheading, which means removing the spent flowers before they set seed. This action limits the plant’s spread and encourages new blooms throughout the summer and fall.
For large plantings, a technique called shearing can be used, where the plant is cut back by about one-third of its height in mid-summer. This practice removes developing seed heads all at once, controlling the spread while stimulating a fresh flush of new blooms. Promptly removing the cut material from the garden bed prevents mature seeds from dropping onto the soil.
Managing volunteer seedlings that sprout in unwanted locations is also a necessary control measure. Blanket flower seedlings are easy to identify and pull, especially when the soil is slightly moist. Removing these young plants early in the spring prevents overcrowding, which can reduce air circulation and make mature plants susceptible to issues like powdery mildew.
Gardeners can also limit spread by strategically planting the blanket flower where it faces competition from other, taller plants. This competition for sunlight naturally reduces the number of germinating seedlings. For a physical barrier, sinking a simple edging material into the ground helps define the boundary for established root crowns.
How to Intentionally Propagate New Plants
Gardeners can intentionally multiply their stock of blanket flower using methods distinct from natural self-seeding.
Division
Division is a common technique for renewing and propagating mature perennial clumps, which often become short-lived after two or three years. This process is best done in early spring or fall. Dig up the entire plant and separate the tight crown into smaller, viable sections, ensuring each piece has healthy roots and foliage.
Seed Collection
Collecting and sowing the seeds oneself offers control over where the new plants establish. Allow a few desirable blooms to completely dry out on the plant until the seed heads turn brown, typically in early autumn. The seeds can then be collected and sown directly outdoors in the spring after the last frost, or started indoors four to six weeks earlier.
Stem Cuttings
Stem cuttings provide a way to ensure that new plants are genetically identical to the parent, which is especially beneficial for hybrid varieties that may not “come true” from seed. This involves taking four to six-inch sections from healthy stems. Dip the cut end in a rooting hormone and plant them in a moist rooting medium. This method is highly effective for maintaining specific cultivar traits.