Let’s Think About Plants That Thrive Hot, Dry Summers
I am so done with snow. I don’t even want to talk about it. Instead, I’ve been immersing myself in the magical world of sun loving plants that thrive on heat and drought. What a delightful idea that is right now, and how appropriate. After the scorching summers and brutal winters of recent years, so many beds and borders have gaping holes where long-time favorite plants lost their will to live. Instead of reflexively replacing them with more of the same, let’s investigate some tougher plants that might actually enjoy situations that were way too challenging for our dear departed.
While we’re doing our research, we can also busy ourselves with refreshing beds and border with a generous layer of compost mulch. I know, I’m always going on about compost, but seriously, there are very few things we can do for our soil with greater benefits than annually refurbishing soil humus. Homemade or trucked in, compost is quite truthfully garden gold. Mulching, whether with compost or aged manure or even straw and autumn leaves is a healing practice that can transform crappy soil in amazingly short order. Don’t think so? Spread a bale of straw over a funky area and let it stand until May. Even in that short time you’ll see more worm action and more open soil under the straw blanket. Leave it in place until September and you’ll notice even more healing. Spread straw—or leaves and grass clippings or manure and compost—every fall and your garden will be transformed. No joke.
Green Manure And Great Plants
Another thing that’s just as valuable is to make a regular practice of growing cover crops in our vegetable beds during the off season. Healing and replenishing the soil is definitely the key to pleasing plants of all kinds. Some growers even under-sow main crops with lower growing green manure crops like annual clovers to get the benefit even as they get a marketable crop. In ornamental beds, that’s not so practical, but annual mulching will help event difficult soils hold more water and host more of the soil biota that bring soils to life. Feed the soil and the soil will nurture your plants. Not only that, you’ll be doing less and less watering as plant roots get down deep in your steadily improving soil.
It used to sound like a joke when we’d explain that the maritime Northwest has a modified Mediterranean climate, meaning that most of our rainfall comes in the cooler months. Back in the day, I’d always quip; just like the Mediterranean without the sun! Hahaha. Yes, Northwestern summers have been relatively cool, yet the past decade saw the hottest years on record. If thirsty border beauties couldn’t cut it, Mediterranean plants managed quite well. Lovely, often aromatic subshrubs from rosemary, lavender, and sage to santolina, artemisia, and horehound (Ballota) thrive in hot, dry conditions. Lesser known but still widely available are handsome evergreens like Jerusalem sage (Phlomis italicum), aromatic Teucrium chamaedrys, and silvery-leaved Brachyglottis greyi (aka Senecio), all sturdy heat lovers.
Natives Plus For Sun
The new summer heat also pleases many native plants from Oregon and California as well as plants from parts of Central and South America, Australia, and New Zealand. The wise gardener will choose plants that are both drought and heat tolerant, such as the shrubby manzanitas (Arctostaphylos) and California lilacs (Ceanothus), both of which offer dozens of handsome, shapely garden-worthy selections. Beloved of bees and butterflies, Asian bluebeards (Caryopteris sp) are long blooming subshrubs and perennials with vivid blue flowers and green or golden foliage. Improved forms like Beyond Midnight and Sapphire Surf have lustrous foliage and generous bloom spikes, while Blue Balloon forms naturally rounded mounds that don’t need shearing to keep their shape.
When the heat is on, tougher beauties can take the place of fussy perennials. Yarrow is among our most adaptable native plants, a circumpolar perennial found throughout most temperate regions. Achillea millefolium has zillions of selected forms, with blossoms of apricot and salmon as well as plum and cream. The lovely New Vintage series ranges from white to rose to violet, fading attractively instead of turning brown. These sturdy perennials make excellent cut flowers and once established, thrive with very little care. Most tickseeds (Coreopsis) revel in full sun, notably the Sizzle & Spice series, including Zesty ZInger, with hot red-to-silver petals; tawny copper-orange Crazy Cayenne; and flame-licked golden Curry Up, all bee and butterfly favorites.
But Wait, There’s More
Let’s not forget the splendid Euphorbia clan, which is packed with sun loving toughies. Surely we can find room for E. characias Silver Swan, with slim, blue-grey foliage edged with silver, and the blazing beauty, E. polychroma Bonfire. The stunning E. x martini Ascot Rainbow, with its lovely rose-to chartreuse-to sage and cream coloration, is happy in shade or full sun. Sturdy woodland spurges, such as E. amygdaloides Red Velvet and Ruby Glow, do best with morning sun and afternoon shade. I love this family and use the best of them frequently, as there’s a Euphorbia for pretty much any spot you can name. Yes, you have to keep that sap off your skin but that’s what gloves are for, right?
I’ve always loved cottage annuals like Moss Rose (Portulaca), which open silky little blossoms even when grown in cement cinder blocks in sifting sand at the beach. Coastal gardeners will also find Ice Plant (Delosperma sp.) rugged and enduring in sun-soaked spots. These once-humble beauties now come in dazzling forms like Fire Spinner, a knockout with copper-to-magenta petals, and Starburst, thickly fringed in hot pink. Outstanding among annuals, heat loving zinnias are the darlings of trendy florists these days, from gorgeous creatures like Zinnia Queeny Lime Orange (my absolute favorite of all time) to the adorable, frilly Zinnia Cupcake series, which make luscious and long lasting cut flowers. So don’t look back! Onward!