Plant Profiles: Heucheras

Heuchera 'Peach Flambe', planted in a shady pot and neglected dreadfully since 2009, yet still going strong. 

Regular readers know I like heucheras a lot, a genus I discovered for the first time when I was deciding what to do with the design and planting of VP Gardens 15 years ago.

At that time the choice available had started to explode, mainly due to the breeding developments by Dan Heims in Oregon and Thierry Delabroye in France. Before then, cultivars were mainly darkish green with red flowers - hence their common names 'coral flower' and 'coral bells' - with pink or white flowers by way of variation.

Now the choice embraces the darkest of blacks through to the limiest of greens, with plenty of hints of caramel, ginger and mottling along the way.

Most heucheras are front of border plants, though their airy loved-by-bees flowers make them seem much taller

The garden's sometimes resembled an archaeological dig this year after my clearing away the shrubbery, with some forgotten heucheras brought blinking back into the light, despite my placing them at the front of the border. It's interesting to see which ones have withstood this treatment - H. 'Licorice', H. 'Obsidian', H. 'Green Spice', H. 'Silver Scrolls', and H. 'Chocolate Ruffles' have definitely stood the test of time.

I confess my dalliance with the lime-green (H. 'Key Lime Pie' and H. 'Lime Rickey') and caramel (H. 'Creme Brulee') varieties has come to an end. Despite their shady setting the lime green varieties tended to become washed-out looking and H. 'Creme Brulee' always seemed like it was at death's door.

There is one exception that proves the rule at VP Gardens; the pictured gigantic-leaved H. 'Brownies' loves the spot I've given it in the double terrace beds, though I confess I do cut off the older, lighter coloured leaves when they start looking sorry for themselves. Note to self: must do that soon.

The lighter and caramel cultivars helped me understand why heucheras don't have universal approval - they can be a bit of a 'Marmite' plant. Don't be put off by my remarks if you like them, I've seen them looking good in other settings; it's me and my garden that's at fault.

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Cultivation Notes

Heucheras are a tough,  fully hardy evergreen plant suitable for most spots towards the front of the border, though they're usually happiest in dappled or light shade. A general rule of thumb is the darker the leaf, the more sun tolerant they are. I've found that full sun or heavy shade tends to produce smaller plants.

They prefer moist, well-drained soils, though I've found they do well on my lime clay soil as long as I don't put them in the wettest part of the garden. They can heave themselves out of the soil, and I've simply reburied a healthy looking part of the root which tends to do the trick.

Hairy leaves keep slugs at bay

The literature say they're a short-lived perennial, but some of my plants are 15 years old. Perhaps my heave/rebury cycle has successfully replaced the divide every 2-3 years I've seen in most guidance. In the spring I give my plants a general tidy up by removing dead and damaged leaves, plus any remaining old flower stems.

They're a magnet for vine weevil, so much so I quarantine my heucheras for a few weeks before planting them out. I've found even heavily attacked plants can recover; if you can find a piece of root with just one root hair left, then this is enough to make a new plant from what initially seems a disaster. I also treat my potted heucheras with nematodes in the spring and autumn as a matter of routine.

I didn't know until I researched this piece that there are 2 species of nematode available, Steinernema kraussei and Heterorhabtidis megidis. It's important to know which one you have because they become effective at different soil temperatures, a minimum of 5^oC and 12^oC respectively. As the temperature is needed for a minimum of 2 weeks after application (and they need soil moisture too), this can have a major effect on when each species can be applied.


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You may also like:

• My look at H. 'Lime Rickey' for ABC Wednesday 
• My Heuchera Haul post from my Open Garden blog in 2008, showcasing some of the cultivars I was growing at the time
• Glimpses of H 'Blackbird', H. 'Blackout' and H. 'Chocolate Ruffles' in previous posts
• My trip to Mount St. Helens in Washington State USA, where I found Tiarella trifoliata - a close cousin of the heuchera - growing in the wild 
• Val Bourne's article from The Telegraph in 2003. She talks about the inclusion of 201 cultivars in the RHS's 1999-2001 trials, which shows how much the choice has exploded since then. I have the H. 'Palace Purple', H. 'Pewter Moon' and H. 'Mint Frost' she mentions, in my garden.

Anyone wanting to know more about heucheras will enjoy Dan Heims' book Heucheras and Heucherellas. The only caveat I have now is it doesn't cover the latest cultivars and there's loads of them, thanks to his and Thierry Delabroye's work. 

For the latest list, look at heucheras.com, which claims to be the complete database of all things heuchera. A search for 'heuchera' on the RHS website, returns a list of 621 possibilities.

The National Collection of Heuchera is at the Plantagogo nursery near Crewe.

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Latin without tears

Heuchera is named after Johann Heinrich von Heucher (1677 - 1746), a Viennese-born physician who was also a keen botanist specialising in medicinal plants. The plants are native to Canada, USA and northern Mexico.

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