Agastache: The Must-Have Plant for Every Garden

Agastache, commonly known as hummingbird mint or hyssop, is a versatile and captivating perennial that deserves a place in every garden. Renowned for its aromatic leaves and long-lasting, colorful flower spikes that persist throughout the summer and into fall, sometimes even until frost, Agastache offers a multitude of benefits for both novice and experienced gardeners. This comprehensive guide will delve into the unique features of Agastache, explore its various aspects, and provide valuable insights into its native habitat, landscaping design tips, and essential planting and care instructions.

What is Agastache?

Agastache is a genus of aromatic flowering plants belonging to the mint family (Lamiaceae). Most Agastache species are native to North America, with a significant concentration in the southwestern United States and northern Mexico. These plants are renowned for their long-lasting flower spikes and ability to tolerate heat and early frosts. Some species, like A. foeniculum (Anise hyssop), are also used in herbal medicines and teas.

Common Names and Varieties Agastache is known by several common names, each highlighting a different characteristic of the plant:

There are about 30 species of Agastache, with four commonly found in gardens: Agastache foeniculum, Agastache mexicana, Agastache rugosa, and Agastache rupestris. Some popular varieties include:

• 'Blue Fortune': This hybrid variety features lavender-blue flowers and is known for its hardiness and long bloom time.
• 'Black Adder': This variety has violet-red flowers and a compact growth habit.
• 'Firebird': With its coral orange flowers, this variety is a favorite of hummingbirds.
• 'Golden Jubilee': This variety stands out with its chartreuse-colored foliage.
• 'Summer Breeze': This variety boasts a long bloom time and a delightful fragrance.
• 'Blue Boa': Characterized by large, deep purple-blue flowers, a long bloom time, a stiffly upright habit, and excellent vigor. This cultivar is a selection from a breeding line using Agastache rugosa as a parent to provide cold hardiness and wet soil tolerance.

In addition to these, the Kudos™ Agastache series deserves special mention. This series was specifically bred for increased tolerance to moisture and cold, expanding the potential growing range of Agastache and making it suitable for more diverse climates. These hybrids combine the traits of Southwestern US and Mexican species, which tolerate heat and drought, with Agastache rugosa, an Asian species that better tolerates moisture and colder winters. Kudos™ plants are more compact and tidier, with dense, long-flowering blooms that retain their colorful calyxes even after the flowers fade.

Physical Characteristics Agastache plants typically grow between 1 and 3 feet tall, with a similar spread. However, some species can reach up to 6 feet in height. They have an upright, clump-forming habit with sturdy square stems characteristic of the mint family. The leaves are generally lance-shaped with toothed edges and come in various shades of green, gray-green, or gold. When crushed, the leaves release a fragrant aroma, often reminiscent of anise or licorice. For instance, A. rupestris has a unique "root beer" scent.

The flowers of Agastache are arranged in dense, terminal spikes, creating a striking display. They come in a wide array of colors, including blue, purple, pink, orange, and white. The individual flowers are tubular and two-lipped, typical of the mint family.

Native Habitat Agastache species are predominantly found in dry and often hilly areas of North America, China, and Japan. They thrive in full sun and well-drained soil. Varieties from Mexico and the Southwest US require excellent drainage.

Agastache foeniculum, or anise hyssop, is native to prairies, dry upland forested areas, plains, and fields in the upper Midwest and Great Plains of North America. It prefers full sun to partial shade and tolerates a wide range of soils as long as they are well-drained. It is hardy to zones 3-8.

Agastache rugosa, or Korean mint, is native to moist grasslands, valleys, and stream banks in China, Vietnam, Laos, Korea, and Japan. Unlike the more drought-tolerant native species, A. rugosa and its hybrids are better suited to the more humid climates of the eastern US.

Landscaping Design Tips Agastache's versatility, long blooming period, and ability to grow in both the ground and containers allow for greater flexibility in garden design. It is an excellent choice for various garden designs:

• Perennial Borders: Agastache adds height and color to perennial borders, especially in mid-to-late summer when many other plants are fading. Its upright habit provides structure and visual interest, while its vibrant flower spikes create focal points within the border.
• Butterfly Gardens: The nectar-rich flowers of Agastache are a magnet for butterflies, making it an essential component of any butterfly garden. Combine it with other butterfly-friendly plants like Buddleja (butterfly bush), Asclepias (milkweed), and Echinacea (coneflower) to create a haven for these beautiful pollinators.
• Cottage Gardens: Agastache's informal growth habit and vibrant colors blend seamlessly into cottage gardens. Its long blooming season ensures continuous color throughout the summer and fall, complementing the relaxed and abundant style of cottage gardens.
• Herb Gardens: Some Agastache species, such as anise hyssop (Agastache foeniculum), have culinary and medicinal uses, making them suitable for herb gardens. The leaves can be used to make tea or add flavor to salads and other dishes.
• Xeriscapes: Agastache's drought tolerance makes it a valuable addition to xeriscapes or dry gardens. Combine it with other drought-tolerant plants like Lavandula (lavender), Salvia (sage), and Perovskia (Russian sage) to create a water-wise landscape that requires minimal irrigation.
• Containers: Agastache can be grown in containers, provided they are placed in a sunny location and have adequate drainage. Choose compact varieties for smaller containers and taller varieties for larger pots.

When designing with Agastache, consider the following:

• Color Palette: Agastache flowers come in a wide range of colors, allowing you to create vibrant displays by pairing them with plants that have complementary or contrasting colors.
• Companion Plants: Agastache combines well with various perennials, including Echinacea (coneflower), Rudbeckia hirta (black-eyed Susan), Sedum (stonecrop), Salvia (sage), Lavandula angustifolia (English lavender), and Crocosmia (Montbretia).
• Height and Spread: Choose Agastache varieties that fit the scale of your garden, considering their mature height and spread.

Planting and Care Agastache is relatively easy to grow and care for, requiring minimal maintenance once established. Here are some essential guidelines:

Planting

• Timing: Plant Agastache in spring after the danger of frost has passed.
• Location: Choose a sunny site with well-drained soil.
• Soil Preparation: Loosen the soil and amend it with compost to improve drainage and fertility.
• Spacing: Space plants 12 to 15 inches apart.
• Self-Sowing: Agastache readily self-sows, especially in colder climates. If you want to prevent this, deadhead the flowers before they go to seed.

Care

• Watering: Water regularly until plants are established, then water occasionally as needed. Agastache is drought-tolerant once established.
• Fertilizing: Agastache prefers lean soil and typically does not require fertilizer. Over-fertilization can negatively impact the plant's growth and flowering, causing it to produce fewer blooms and become floppy.
• Mulching: Mulching is generally not necessary, but a thin layer of pine needles or crushed stone can help retain moisture and suppress weeds.
• Pruning: Deadhead spent flowers to encourage rebloom. In late winter or early spring, cut back the remaining stems to the ground.
• Dividing: Divide plants every 3 to 5 years to rejuvenate them.

Propagation Agastache can be propagated from seed or cuttings.

• Seed Propagation: Sow seeds in early spring when the soil temperature is between 55-64°F. Start seeds indoors 4-6 weeks before the last frost or sow directly into the garden after the last frost.
• Cuttings: Take semi-ripe cuttings in summer. Dip the cut ends in rooting hormone and plant them in a moist potting mix. Keep the cuttings in a warm, humid environment until they root.

Unique Features Agastache possesses several unique features that make it a valuable addition to any garden:

• Pollinator-Attracting Properties Agastache is a favorite of pollinators, including bees, butterflies, and hummingbirds. Its nectar-rich flowers provide a valuable food source for these beneficial insects and birds. The tubular shape of the flowers is specifically adapted to attract hummingbirds and butterflies, making it an excellent choice for pollinator gardens.
• Potential Medicinal Uses Some Agastache species have a long history of use in traditional medicine. For example, anise hyssop (Agastache foeniculum) has been used to treat colds, fevers, and digestive issues. Korean mint (Agastache rugosa) is used in traditional Chinese medicine to improve appetite and strengthen the digestive system. Studies have also shown that Agastache species have a range of pharmacological effects, including antioxidant, cytotoxic, and antimicrobial properties, highlighting the potential health benefits of the plant.

Other Notable Features

• Deer and Rabbit Resistance: The strong fragrance of Agastache tends to deter deer and rabbits, making it a low-maintenance choice for gardeners.
• Long Blooming Period: Agastache blooms from early summer to early fall, providing a long season of color and interest in the garden.
• Fragrant Foliage: The aromatic foliage of Agastache adds another dimension to the garden, releasing a pleasant scent when brushed against or crushed.
• Edible Flowers and Leaves: Some Agastache species have edible flowers and leaves that can be used in teas, salads, and other culinary creations. For example, the leaves of anise hyssop can be used to make a refreshing tea or added to salads for a unique flavor. The flowers can be used as a garnish or added to desserts.

Agastache is a remarkable plant that offers a wealth of benefits for gardeners. Its adaptability to various growing conditions, combined with its long blooming period, vibrant flower colors, and attractive foliage, makes it a versatile and low-maintenance choice for any garden. As a pollinator magnet, Agastache contributes to the ecological balance of the garden, attracting beneficial insects and birds that help with pollination and pest control. Furthermore, its potential medicinal uses add another layer of value to this already exceptional plant. Whether you are a seasoned gardener or just starting, Agastache is sure to become a favorite in your garden, providing beauty, fragrance, and ecological benefits for years to come.