Get Growing: Bridge the seasons with long-bloomers

Once you’ve gardened awhile, you see there are seasons within seasons in the border. The dream is to have something in bloom nearly every week of the year — which, thanks to our climate — is within reach for Seattle gardeners, with some space and planning. The Bellevue Botanical Garden’s Perennial Border is an excellent example.

Of course, it’s fine to have lulls in your garden — maybe you prefer to have two or three blockbuster blooms rather than stretching a variety over a longer period. For instance, a border with spring bulbs followed by daylilies or dahlias. Today, I’ll deal with extending your flower power during those lulls by choosing plants wisely.

Mind the gap

There are a great many plants that bloom from April into mid-May, and many from June into July, so it’s relatively easy to cover those periods.

To bridge the gaps, consider some of these powerhouse plants that choose to bloom earlier and later.

Ornamental onion

Allium bulbs, particularly the large varieties, bloom a long time, and even when officially past their prime, their unusual globe-shaped flowers stay upright but faded, adding structure and height for weeks. Some even spray paint them for color into fall! Some varieties to look for include “Globemaster,” “Purple Sensation” and “Mount Everest.”

These perennials are usually purchased and planted in bulb form in fall, but nurseries are carrying potted ones now.

Wallflowers

Erysimum hybrids, also known as wallflowers, are some of the blooming-est plants you’ll ever find. They were doing High Intensity Interval Training before it became trendy. While technically perennial, they may fade out after several years out of sheer exhaustion. New varieties come in a host of sunset colors with names like “Winter Orchid” and “Apricot Twist,” while “Bowles’ Mauve” is an heirloom favorite.

Some are highly fragrant, so test before buying if this is important to you. They begin blooming in April and can continue for two months if deadheaded. Summer brings a well-earned rest, but if you trim them back and offer some compost and liquid fertilizer, you’ll see renewed blooms in September. They prefer well-drained soil and can take partial shade. Pollinators love these too.

Calendula

Another precocious bloomer that likes the weather on the cool side, calendula starts in May and blooms through July if deadheaded and watered in the heat. Like erysimum, they will perk up again when the heat of summer fades for a second show if trimmed and watered through the summer. As a bonus, calendula flowers are edible, making lovely additions to salads and summer beverages and are a common ingredient in natural salves and creams. These are “half-hardy annuals” that can seed around, but I always find them a welcome presence. You can sow them in autumn or earliest spring or buy started plants now.

Perennial geraniums

Let’s get the names clear first. Botanically, these plants, like geranium endressii, or G. pilostemon, own the name geranium, rather than the pretender window-basket annuals who took it over — those are really called pelargonium. These are mat-forming perennials that make a great groundcover, bloom for months and host pollinators, too. Their leaves often take on red fall tones, too. They’re not evergreen, but you can’t have everything. The best I’ve found so far is geranium “Rozanne,” which blooms in violet blue on my very dry hillside from April through October. Seriously.

Agastaches

The blue/purple agastaches have proven strong performers in my parking strip, which is even worse soil than my dry hillside. While I adore the orange and yellow agastaches, the blooms are more sparse, and the plants seem flightier. The optimistically named “Blue Fortune” and “Blue Boa” offer showy, cattail-like blooms — with “Fortune” being more blue, and “Boa” being more violet. They emerge early, ready to cover over dying spring bulb foliage, and bloom from May through October, helped with a bit of deadheading, which you won’t mind because it releases a delightful minty fragrance.

Rudbeckias

More reliably perennial in most situations than echinaceas, the rudbeckia family includes many stalwart bloomers for late-season color, from the old standby black-eyed Susan “Goldsturm” and “Henry Ellers” for front and mid-border to lesser-used tall varieties like R. iacinata (cutleaf coneflower — droopy lemon petals with a green eye) or giant R. maxima with a black center. The black-eyed Susans don’t even get started until July and then just keep going until October. Note that the appealing R. hirtas that appear in nurseries in July like “Cherry Brandy” in rusty red are not typically perennial. 

Annuals

Pelargonium, what many call geraniums, may be the longest-flowering annual for a sunny spot. Pair it with fragrant alyssum, and you have a bulletproof combo for the season. The alyssum may even return if it’s happy. Pansies and especially their wilder viola cousins, bloom super-early, sometimes shrugging off snow, for about two months and reprise their performance in fall if given compost and water. Certain violas, like “Molly Sanderson” and “Etain” may return and expand over the years. Try sprinkling some of these into your border plans and watch them boost your flower power.