rosette [ roh-ZET ] noun: a circular arrangement of leaves or other organs
Although a rosette conjures up the petals of a rose, leaves clustered tightly in a circular or spiral arrangement come in many shapes and sizes. They may be terminal rosettes at the end of stems or basal rosettes near the soil. Basal leaves grow at or near the plant’s crown, which is the thick part of the stem where the roots attach. A number of desirable and undesirable species produce basal rosettes, so being able to identify a species in its different forms will help prevent mistaking the rosettes of preferred plants for weeds and inadvertently digging up or mulching over them.
Some basal rosettes are ubiquitous and commonly recognized as weeds, like non-natives Taraxacum (dandelion), Plantago (plantain), and Cirsium (thistles). The rosettes of stoloniferous perennials like native Erigeron pulchellus (Robin’s plantain) and non-native Ajuga reptans (bugleweed) can form desirable ground covers, although the latter has been known to escape gardens and invade lawns and woods. For other perennials with basal rosettes, like Papaver orientale (Oriental poppy), the entire plants die back in summer heat after flowering, leaving an empty space in the garden. However, in fall the basal rosettes reemerge, overwinter, and in spring grow vertically producing flowers once again.
Short-lived perennials or biennials may produce in their first year a basal rosette that overwinters and in the second year a central stem that flowers. Native Lobelia cardinalis (cardinal flower) overwinters as an evergreen rosette so be sure not to suffocate it with mulch or leaf litter. It sends up a flowering stem the next season and usually produces several basal offshoots, after which the original rosette dies. The cycle of overwintering rosettes, late-summer flowering stems, and new offshoots increase the size of the clump for three to five years; the plant also easily reseeds. The basal rosette of non-native Verbascum thapsus (woolly mullein) may be over two feet wide and its flowering stem up to six feet high. The plant usually dies after its second year and perpetuates by self-seeding.
Basal rosettes, like ornamental kale and cabbages, can find a home in containers or in edible gardens. Some succulents can grow as houseplants, like aloes with their fleshy, lanceolate, serrate leaves that form rosettes and reproduce by offsets. Others can grow outdoors in pots or rock gardens or under trees and shrubs. Evergreen Sempervivum (hens and chicks) forms colonies with its original rosette (the hen) and offsets (the chicks). Individual rosettes die after bloom. Sedums, like native, semi-evergreen Sedum ternatum (wild stonecrop), often have stems with leaves in terminal rosettes. Some lichens, algae, and bryophytes can also grow in the shape of rosettes.
Illinois Wildflowers, © 2002-2012 by John Hilty. (accessed April 19, 2022).
Minnesota Wildflowers. (accessed April 19, 2022).
Plants. North Carolina Cooperative Extension. (accessed April 19, 2022).
Weakley AS, Ludwig JC, Townsend JF. 2012. Flora of Virginia. Botanical Research Institute of Texas.
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