Scented nettles

Plant family

Mint family (Lamiaceae)

Also known as

Blue Giant Hyssop, Fragrant Giant Hyssop, Lavender Giant Hyssop

Season Overview

Details

Light requirement

Sunny

Water requirement

Dry

Soil

Medium (loamy)

Nutrient requirement

Medium

Light germinator

Germination temperature

20 – 25 °C (Degrees Celsius)

Plant distance

50 cm

Row spacing

50 cm

Seeding depth

0.5 cm

Instructions

Description

Origin The fragrant nettle (Agastache) with its pretty flower candles, refreshing fragrance and very long flowering period has been gaining more and more fans among hobby gardeners for several years now. The flowers of the fragrant nettles, which belong to the Lamiaceae family, also attract numerous insects and the flowers and leaves of the various species can even be harvested and eaten. The names of the species and varieties of this perennial genus are somewhat confusing. Some are called scented nettle or mountain mint, others - based on the blue flower candles of some species - are called blue nettle and some are misleadingly called hyssop, although they are only distantly related to the true hyssop (Hyssopus). Appearance and growth The growth habit of the Agastachen is strongly dependent on which group the respective species belongs to. Fragrant nettles can be divided into two groups. The four species and their varieties from China, Korea and North America, which belong to the first group of garden perennials, not only grow considerably taller than the species in the second group, they also grow very bushy. Their upright stems, which are covered all over with highly fragrant, broad leaves, form dense clumps. These species can reach heights of up to 2.50 meters. The thermophilic species that make up the second group remain somewhat lower and are characterized by a more loosely branched growth habit. None of them grow taller than one meter and some barely reach the 30-centimetre mark. However, it's not just the growth, but also the foliage and flowering that differ. While the flowers of the four garden perennials are in dense false spikes and are usually white or blue in color - Agastache nepetoides is an exception here with yellowish-green flowers - the species in the second group present a colorful bloom that can be pink, red or even orange, depending on the species and variety. In contrast to the rather compact spikes of the first group, they are not only larger but also arranged in groups or whorls and the individual flowers are rather loose. What both groups have in common, however, is their flowering period, which extends from the end of June to September, depending on the species and variety. The leaf shape of the second group is more linear compared to the broad, egg-shaped foliage of the first. Depending on the species and variety, the leaf edge can be toothed or smooth. All species of scented nettle are also characterized by their square stems and the striking aniseed or fennel scent that the leaves exude when crushed.

Growing tips

Location and soil As a general rule, scented nettles are more hardy the drier they are. The perennials cannot cope with waterlogging and wet winters. A planting site in full sun with nutrient-rich, well-drained soil is ideal. Agastache rugosa and its hybrids are the only plants that can tolerate slightly damper and heavier soils; all others should be made more permeable with sand. Planting Agastache in pots can be planted from spring to fall. If the soil in your garden is not very rich in nutrients, you should improve it with a little well-rotted compost before planting. Care tips In a sunny spot with dry, well-drained soil, Agastachen will seed abundantly. This is good, as the perennials are often not particularly long-lived. If you find sowing troublesome, you can cut the candles back before the seeds ripen - but then you will have to do without the beautiful winter silhouette that tall varieties in particular bring structure to the perennial bed even in the cold season. Long-lived fragrant nettle species and their hybrids can be divided in spring and thus propagated and rejuvenated at the same time. Also in spring, give the perennials a dose of compost or another organic fertilizer to help them sprout new shoots and get the new season off to a good start. Use In summer, fragrant nettles are eye-catchers in the perennial bed alongside Indian nettle (Monarda), coneflower (Rudbeckia), globe thistle (Echinops), phlox or widow's flower. The eye-catching false spikes of the species used as garden perennials make them ideal for combining with perennials with other flower shapes. For example, the compact spikes are shown to their best advantage in combination with species such as goldenrod (Solidago) or Gaura, which tend to have loose inflorescences. Typical autumn grasses such as switchgrass (Panicum virgatum) are also great bedding partners. The deep blue-violet of some scented nettle varieties, for example the Agastache rugosa hybrids 'Black Adder' or 'Blue Fortune', forms a particularly beautiful contrast to yellow-flowering perennials. Some species of scented nettle can also be used in the kitchen. The aroma of the fragrant nettle (Agastache rugosa), which originates from South East Asia, is reminiscent of mint and aniseed. In Korea, it is used to season pancakes and stews. The Korean mint, as the shrub is also known, is also a wonderful tea ingredient. Aniseed hyssop, which originates from North America, has an intense aniseed-fennel aroma, which is where it gets its name. In the kitchen, it can be used wherever you would use herbs, for example in fish stews or salads. Native to Mexico, Agastache mexicana with its citrus flavor goes particularly well with refreshing drinks. Propagation The longer-lived species of fragrant nettle can be propagated by division in spring. Another method of propagation is via semi-ripe cuttings, which are cut in late summer after flowering. However, these must first be kept frost-free in winter after propagation. As mentioned above, scented nettles also produce plenty of seeds that can be used for sowing. However, this method of propagation only works for the species. The cultivated forms are not true to variety and must therefore be propagated by division or cuttings. Diseases and pests Scented nettles are generally considered to be robust and not very susceptible to disease. Only in persistently damp weather does mildew sometimes occur and slugs can also become a problem.