Tanacetum, a genus that includes plants commonly known as Tansy, Feverfew, and Painted Daisy. This group offers a variety of characteristics, from aromatic foliage to showy flowers, and has a rich history of use.

What Makes Tanacetum So Special?

• Aromatic Foliage: Many Tanacetum species have strongly aromatic foliage, often with a pungent, camphor-like, or citrusy scent. This aroma is released when the leaves are crushed or brushed against, making them interesting additions to sensory gardens.
• Insect-Repelling Properties: The strong scent is also known to repel certain insects, making Tanacetum a traditional companion plant in vegetable gardens and a natural insect repellent.
• Medicinal History: Several species, particularly Tanacetum vulgare (Common Tansy) and Tanacetum parthenium (Feverfew), have a long history of medicinal use. However, it is crucial to note that some species can be toxic, and internal use should only be under the guidance of a qualified healthcare professional.
• Showy Flowers: Some species, like Tanacetum coccineum (Painted Daisy), are grown primarily for their attractive, daisy-like flowers in shades of pink, red, white, and yellow.
• Long Bloom Time: Many Tanacetum species have a long bloom time, providing color in the garden for weeks or even months.

Description

• Flowers: Flower shape varies depending on the species. Some, like T. vulgare, have button-like flower heads composed entirely of disc florets (no ray florets, or "petals"). Others, like T. coccineum, have typical daisy-like flower heads with both ray and disc florets. Colors range from yellow and white to pink, red, and magenta.
• Foliage: Leaves are typically alternate, pinnately divided (fern-like), and often deeply dissected. Foliage color is usually a medium to dark green, and many species have a strong, characteristic aroma.
• Growth Habit: Varies by species. Some are upright, clump-forming perennials, while others are more sprawling or mat-forming. Some are annuals or biennials. Heights range from a few inches to several feet.
• Scent: Pungent and medicinal.

Details

• Bloom Time: Varies by species, but generally summer to fall.
• Hardiness: Varies by species, but many are hardy in USDA zones 4-9.
• Sunlight: Most prefer full sun (at least 6 hours of direct sunlight per day), but some tolerate partial shade.
• Soil: Prefer well-drained soil. Many are adaptable to a range of soil types, including average garden soil, sandy soil, and even somewhat poor soils.
• Drought Tolerance: Varies by species. Some are quite drought-tolerant once established, while others prefer more consistent moisture.
• Deer Resistance: Generally considered deer-resistant due to the strong scent of the foliage.
• Attracts Pollinators: The flowers attract bees, butterflies, and other pollinators.
• Self Seeding: Some readily self-seed.

Native Habitat

Tanacetum species are found throughout the Northern Hemisphere, with a concentration in Europe and Asia. They inhabit a variety of habitats, including meadows, grasslands, open woodlands, and disturbed areas.

Landscaping Design Tips

• Herb Gardens: Tanacetum vulgare and Tanacetum parthenium are traditional additions to herb gardens.
• Cottage Gardens: Their informal habit and often bright colors make them a good fit for cottage gardens.
• Borders: Can be used in mixed perennial borders, providing both foliage texture and flowers.
• Cutting Gardens: Tanacetum coccineum is an excellent cut flower.
• Naturalized Areas: Some species, like T. vulgare, can be used in naturalized areas, but be aware of their potential to spread.
• Companion Planting: Tanacetum is often used as a companion plant in vegetable gardens to repel insects.
• Containers: Compact varieties grow well in pots.
• Caution: Tanacetum vulgare can be invasive in some areas. Check local regulations before planting it.

Planting and Care

• Planting: Plant in spring or fall. Space plants according to their mature size.
• Watering: Water regularly when newly planted. Once established, watering requirements vary by species. Drought-tolerant species need less frequent watering.
• Fertilizing: Generally, do not require heavy fertilization. A light application of compost or a balanced fertilizer in spring can be beneficial.
• Pruning: Deadhead spent flowers to encourage continued blooming and prevent self-seeding (if desired). Cut back plants after flowering to maintain a tidy appearance.
• Division: Divide clumps every few years in spring or fall to rejuvenate plants and propagate new ones.
• Pests and Diseases: Generally, pest and disease-resistant. Aphids, spider mites, and leafhoppers can sometimes be a problem.
• Invasive Potential: T. vulgare, in particular, can be quite aggressive.

Taxonomy

• Kingdom: Plantae
• Phylum: Angiosperms
• Class: Eudicots
• Order: Asterales
• Family: Asteraceae (Sunflower family)
• Genus: Tanacetum

Morphology

• Roots: Fibrous root system, sometimes with rhizomes (underground stems).
• Stems: Erect or ascending, often branching.
• Leaves: Alternate, pinnately divided (fern-like), often deeply dissected, and usually aromatic.
• Flowers: Inflorescences are heads (capitula) that may be solitary or arranged in corymbs (flat-topped clusters). Flower heads may be composed entirely of disc florets (as in T. vulgare) or have both ray and disc florets (as in T. coccineum).
• Fruit: A small, dry achene.

Popular Varieties

• Tanacetum vulgare (Common Tansy): Tall, upright perennial with button-like yellow flowers and strongly aromatic, fern-like foliage. Can be invasive.
• Tanacetum parthenium (Feverfew): Short-lived perennial or biennial with small, daisy-like white flowers and aromatic foliage. Used medicinally. 'Aureum' has golden foliage.
• Tanacetum coccineum (Painted Daisy, Pyrethrum): Grown for its showy, daisy-like flowers in shades of pink, red, white, and yellow. Source of the natural insecticide pyrethrum. 'Robinson's Red' is a popular cultivar.
• Tanacetum balsamita (Costmary): Also, once used medicinally.

Other Insights for Gardeners

• Toxicity: Tanacetum vulgare, in particular, contains compounds that can be toxic if ingested in large quantities. It is best to avoid internal use unless under the guidance of a healthcare professional. Some people may also experience skin irritation from contact with the foliage.
• Invasiveness: Tanacetum vulgare is considered invasive in some regions of North America. Be aware of its potential to spread and take appropriate measures to control it or choose alternative species.
• Pyrethrum: Tanacetum coccineum is the source of the natural insecticide pyrethrum, which is used in many organic insect control products.
• Drying: The flowers and foliage of many Tanacetum species can be dried for use in potpourris, crafts, and insect-repelling sachets.

In conclusion, Tanacetum offers a diverse range of plants with aromatic foliage, attractive flowers (in some species), and a rich history of use. From the traditional herb garden to the colorful cutting garden, there is likely a Tanacetum to suit a variety of garden settings. However, it is important to be aware of the potential toxicity and invasiveness of certain species, particularly T. vulgare. Choosing the right species and managing its growth appropriately will ensure that you can enjoy the benefits of this versatile genus.