Daisies are widely known for their cheerful flowers, but whether they spread depends entirely on the specific species planted. Different daisies employ distinct reproductive strategies that determine their aggressiveness and the required maintenance. Understanding the growth habit of your particular daisy is necessary for managing its presence in the garden and controlling its population.
Understanding Daisy Growth Habits
Daisies utilize two primary mechanisms to expand their territory, which varies between common garden types. The English Daisy, Bellis perennis, is a low-growing perennial that spreads vegetatively using underground runners or offsets. These runners, known as rhizomes, are modified stems that grow horizontally beneath the soil surface, forming dense, spreading mats. This aggressive, mat-forming nature allows Bellis perennis to colonize an area quickly, often classifying it as a lawn weed.
Conversely, the popular Shasta Daisy (Leucanthemum x superbum) and the Oxeye Daisy (Leucanthemum vulgare) primarily spread through prolific seed dispersal, a process called self-seeding. Once flowers fade, viable seeds mature and are scattered by wind, water, or wildlife. While Shasta daisies also form large clumps and spread slowly via short rhizomes, their main strategy involves producing numerous volunteer seedlings. Management must therefore target either the underground stems or the seed production cycle.
Controlling Spread Via Underground Runners
For daisies that spread aggressively using subterranean stems, such as the English Daisy, physical containment and regular division are the most effective control methods. These plants create a network of rhizomes, allowing new plantlets to emerge away from the original crown. To maintain plant vigor and prevent overcrowding, perennial clumps should be dug up and divided every two to three years, typically in early spring or after flowering. Division involves separating the mat into smaller sections and replanting only the healthiest, outer portions, discarding the older, woody center.
For aggressive species, physical barriers can be installed to restrict the rhizomes’ lateral movement. Burying plastic or metal edging around the planting area acts as a subterranean wall, forcing the runners to stay within the designated boundary. If complete removal is necessary, all rhizome fragments must be carefully extracted, as any small piece containing a node can regenerate a new plant.
Preventing Spread Through Self-Seeding
Controlling the spread of daisies that primarily reproduce through seed requires focusing on the flower’s reproductive cycle. The technique known as deadheading is the most effective action to prevent self-seeding in varieties like the Shasta Daisy. Deadheading involves removing the spent flower heads before they mature into viable seeds. This conserves the plant’s energy, redirecting it toward producing more flowers or strengthening the root system.
Deadheading should be performed as soon as the petals fade or the central yellow disk begins to turn brown, signaling that seed development is underway. Gardeners should use sharp shears to cut the entire flowering stem back to a set of healthy leaves or a new growth point. Removing any tiny volunteer seedlings that sprout in unwanted locations also helps manage the population.