10 beautiful but tough perennials for too wet and too dry summers

March 17th, 2023
Posted In: Gardening know how

We all want beautiful but tough perennials in our gardens this year.

Temperate climates (those with spring, summer, autumn and winter seasons) are notoriously changeable.

At Antique Perennials, Kinglake, Australia’s top perennial nursery, they know all about unexpected weather extremes.

At first glance, the weather at Antique Perennials seems similar to that of South East England, Seattle in the US or Paris in France. ‘Average’ summer temperatures are theoretically in the low 20Cs and average winter temperatures generally a few degrees above freezing in night-time.

But ‘average summers’ are rare anywhere with temperate climate. Antique Perennials has often experienced long, hot dry summers, with temperatures regularly in the 30Cs.

However, it was the UK that hit 40C last summer, with weeks of drought, while Antique Perennials had cooler weather (20Cs) with heavy rain. At one point, a whole year’s worth of rain fell in just one month. Mike Morant of Antique Perennials says that they now have more rain than London does.

The shop and garden at Antique Perennials

So he picked out 10 perennials that have done well in both their hot, dry summers and the more recent cool, very wet weather. You’d expect to find the plants available in the UK, the US and Australia. Most will grow well in Zones 5-9 in the US, all of the UK and parts of Australia, New Zealand, Canada and Northern Europe.

When I was checking other charactistics of these plants, I could see that some were labelled ‘drought tolerant’ on other sites, but they weren’t listed as being tolerant of heavy rain.  However, as Mike pointed out, Antique Perennials had four months this year when plants in the Antique Perennials garden were almost standing in water. These plants have emerged well.

Achillea Moonshine (Yarrow)

An upright yarrow with bright yellow foliage, it grows to around 60cm high and doesn’t clump out much so you’ll need to plant several plants to get a good group. Flowers from the summer through to autumn, and is very easy care. Deer and rabbit resistant, but attractive to butterflies and pollinators. Full sun and partial shade. Has an RHS Award of Garden Merit. Hardy down to minus 40C/minus 40F.

A low-growing yarrow, which survives both the hot, dry Australian summer and the four months of torrential rain Antique Perennials had last year.

Allium ‘Millenium’

A pretty low-growing bulb for the front of a border, it reaches 40cm high and clumps out into 45cm wide. Flowering in mid to late summer, it’s highly attractive to pollinators and the spent flower heads have architectural interest. It’s deer and rabbit resistant and has been awarded the US Perennial Plant Association’s Plant of the Year 2018. You can see a similar low-growing allium for the front of borders featured in How to Create a Stunning Perennial Border. Very easy care and tolerant. Hardy to minus 28C/minus 20F.

Mike says that Allium ‘Millenium’ is one of the tough perennials for the front of a border that also works well as a cut flower.

Aster ‘Twilight’ (also known as Erybia x herveyi)

With lots of brilliant blue flowers, this grows well in both sun and partial shade. It grows up to 1m high with a spread of 0.5m. It’s a native of the North East United States, and is loved by butterflies and pollinators. Hardy down to minus 40C/minus 40F. Mike says that many asters are resilient, especially the large leafed ones. He suggests you also try ‘Aster tatarico.’

I was lucky enough to catch this moth tucking on this Aster ‘Twilight’. It’s loved by pollinators, and Mike says that the foliage keeps on looking good, no matter how tough the summer.

Crocosmia ‘Miss Scarlett’

One of the most elegant tough perennials, grown from corms. Mike says that it has slightly darker foliage than some crocosmias and he’s found it more drought and wet tolerant than the crocosmias with paler, more citrus green leaves. A blaze of red for full sun or partial shade. Crocosmia can become invasive in some places, so check if that could be a problem where you are. Hardy down to minus 20C/minus 5F

Crocosmia ‘Miss Scarlett’ in a blaze of red, alongside Agastache aurantiaca, which Mike has found to be a little less resilient in difficult weather.

Lepechinia salviae – Chilean Pitcher Sage

This relative of the salvia family is tall with fragrant, purple flower spikes 4ft-5ft high and 6ft wide. Like most plants in the salvia family, it has fragrant leaves so it deters slugs, snails and deer. Mike particularly commented that its foliage continues to look good right to the end of the summer, and it’s also long flowering. Easy to look after, just cut down the flowering spikes in spring. Not that easy to find, but worth looking for if you like something unusual in your garden. Full sun. Hardy down to minus 10C/15F.

Lepechinia salviae, a salvia relative is a strikingly tall and resilient perennial.

Panicum Blue Steel  (alternative is Panicum Heavy Metal) Also known as Blue Switch Grass.

A striking blue-grey grass which reaches 160cm high x 75cm wide. It keeps a good vertical shape and doesn’t flop, and goes a butterscotch colour in autumn. In late summer, it’s topped with lacy, pretty pink flowers. Antique Perennials is one of the few growers so you may have to look for Panicum Heavy Metal, which is more widely available. US native. Full sun. Hardy down to minus 34C/minus 30F.

Panicum ‘Blue Steel’ was bred by Antique Perennials. It has very handsome blue foliage which turns butterscotch brown in autumn and winter.

If you’re still not convinced that ornamental grasses have a place in a herbaceous border, then see Steve Edney and Lou Dowle’s border in What You Need to Know to Create a Stunning Perennial Border.‘ There’s also a beautiful mix of grasses and other perennials at Marchants Hardy Plants in The Best Time to Plant Perennials.

Persicaria affinis

This is a low growing, mat-forming persicaria, with small pink flower spikes, reaching around 50cm high. Mike says that this smaller persicaria is more drought resistant than the taller ones, which he finds need more water in summer. I’d agree with that – my larger persicaria was one of the plants that dried out in the last very hot UK summer.  Pollinator-friendly and has an RHS Award of Garden Merit. Full sun and partial shade. Hardy down to minus 40C/minus 40F.

Persicaria affinis is a low growing persicaria which doesn’t need as much water as the larger persicarias.

Phlomis russeliana (Turkish sage)

Phlomis russeliana featured in our ‘slug resistant plants’ post. It has pretty yellow flowers in spring, which brown and dry into interesting sculptural shapes. It reaches about 1m high, with a clump of low growing, slightly fuzzy leaves. Full sun or partial shade and very easy care. Wildlife friendly. Phlomis is in this list of snail and slug resistant plants. Hardy down to minus 28C/minus 20F.

Phomis russeliana flowers in spring, then has sculptural seedheads which last through autumn and winter.

Sedum (now Hylotelephium) ‘Autumn Joy’

These hardy sedums were renamed hylotelephium a few years ago by botanists, but most people still call them ‘sedum.’ ‘Autumn Joy’ is otherwise known as ‘Herbstfreude’. Autumn Joy has thick fleshy leaves and big rounded flowers, much loved by pollinators. It grows to around 60cm high and wide. The flowers dry on the plant, creating good winter structure in the border. RHS Award of Garden Merit. Sedum ‘Autumn Joy/Herbstfreude’ are one of the plants listed in 10 low maintenance plants for a long-lasting garden. Hardy down to minus 40C/minus 40F.

‘Autumn Joy’ is a much-loved hylotelephium. Mike has also found the popular ‘Matrona’ to be very resilient in both wet and dry summers.

Stachys ‘Big Ears’

This plant is mainly grown for its low mound of large, grey-green felted leaves. Stachys ‘Big Ears’ has occasional purple flower spikes throughout the summer, but many people snip them off to keep the impression of a carpet of foliage. It’s snail and slug resistant, growing to 45cm high and 60 cm wide. Low maintenance and drought tolerant, it’s one of the easiest tough perennials to grow. Mike says this variety of stachys survived their very wet spring well. Hardy down to minus 34C/minus 30F.

Mike says that this is one of the best tough perennials, with foliage that stays looking good all summer long.

Keeping costs down when buying perennials

It’s worth drawing up a budget when you’re planning your planting. I believe that buying healthy plants from a good independent nurseries is always a good investment. And you benefit from their expertise as the gardeners are usually there to answer your questions. Prices may not be lower, but you’re much more likely to get a long-lasting plant that looks good in your garden. And that means less wastage.

But if you’re going to a garden centre or buying plants online, it’s really worth looking at where you can trim your budget. I’ve researched 8 cost-cutting tips in How to Create a Garden Border on a Budget.

Pin to remember beautiful but tough perennials

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