Agastache stands tall in the border like a supersized salvia, and August is the month when (if you haven’t already) you will fall in love with it. The 1m wands of fluffy lilac flowers and deep purple calyces of Agastache ‘Blue Fortune’ have for some time been my secret to success in bridging the tricky August gap.
Short-lived but long flowering, giant hyssop — its common name — will attract bees and butterflies to its long-lasting blooms from July to October. Slugs and snails, meanwhile, are stopped from nibbling the plant by its aromatic minty-liquorice leaves. After that, the sturdy spires will stand tall through the winter, attracting birds to their elegant seedheads.
The Achilles heel of agastache is winter wet — it needs a very well-drained soil, sand rather than clay, if it is to return the following year. If you garden on clay, you may be lucky, but even then your plant may fall victim to frost, depending on the type you have. Treat this late-summer beauty as annual bedding, and it is so wonderful it bears a repeat purchase.
Seek it out next time you are looking for plants. There are now more varieties than ever, with pinks and oranges and whites as well as the expected palette of lilacs and blues. Sizes range from 40cm to 1m.
Agastache ‘After Eight’
This compact, fully hardy form creates a bush just 50cm in height and spread. A mound of neat, deep green foliage with bronze tints and purple-black stems, it has violet flowers from July to October. Plant in the middle of the border or use as an edging plant.
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A ‘Black Adder’
Dark purple buds elongate into long spikes of smoky-lilac flowers, reaching 1m tall but with a spread of just 40cm. The pale flowers stand out from the deep grey-purple calyces giving an almost fluffy, bottle-brush effect to the plant. Fully hardy, it will flower from July to October.
A ‘Blue Fortune’ AGM
Pale violet blue flowers with lavender calyces appear on long flower spikes (mine were more than 17cm this summer). This erect form will reach more than 1m tall but still be perky and upright. It flowers from July to September and stands well through the winter despite being only borderline hardy.
A ‘Tangerine Dreams’ AGM
The graceful habit of this agastache, with branching stems and loosely spaced flower clusters, gives it an airy feel, quite unlike some of its siblings. The flowers are a gorgeous soft orange with deep terracotta contouring and dark red calyces. Extremely floriferous, it blooms from July to October at 70cm tall.
A ‘Globetrotter’
Vibrant violet flowers and magenta pink calyces make this ideal for a bold colour scheme. The dense flower spikes are slightly shorter than its blue and purple cousins but just as punchy. Flowering from June to September at 1m.
A ‘Painted Lady’
Slightly earlier to flower, from June to September, this borderline-hardy 50cm form is a wash of sun-kissed colours; coral pink and dull orange flowers emerge from smoky heather-pink calyces. Excellent for smaller plots or for planting in a pot, perhaps with Nepeta ‘Kitkat’ and Festuca glauca.
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A urticifolia ‘Alba’
This white agastache is borderline hardy and not as long-lived as coloured varieties, but it comes into bloom at a very useful time, flowering at 90cm from August to September. The white flowers and green calyces will lift the soft blues and hot oranges of neighbouring plants.
A ‘Summer Sunset’
Orange buds open to apricot flowers that flush pink as they mature. Dark purple-plum calyces complement the flowers and provide a rich coppery feel. Plant this 45cm frost-hardy variety in a pot, or as an edging plant and enjoy it from July to October. It would look great with purple or blue companions.
A ‘Cotton Candy’
Another excellent introduction. It has pale pink flowers but its deep red-pink calyces stop it looking sickly sweet. The 90cm flowering stems are a little lax, softly leaning outwards. Enjoy from July to September. Cotton Candy is frost-hardy, but protect it to be on the safe side.
A mexicana ‘Red Fortune’
A frost-hardy variety, with medium pinkish-red flowers and a hint of purple. The soft colour is almost antiqued, without appearing faded or dull, and is one of those colours that blends well in a border. Grow this 60cm agastache for blooms from July to October.