Unity through repetition
Self-sowers provide strength in numbers—many seeds germinate and quickly develop into masses of bloom. Their repetitive appearance in beds unifies the garden and ties color schemes together. For example, bigflowered evening primroses (Oenothera glazioviana) undulate through my beds in waves, providing cohesiveness with their buttery-yellow flowers and strong, upright form. Likewise, billowing masses of tiny snow daisies (Tanacetum niveum) punctuate the beds at regular intervals, their cool-white flowers and sage-green foliage a wonderful contrast to larger, color-saturated blooms.
Some self-sowers have terrific foliage. One of my favorites, red orache (Atriplex hortensis var. rubra), has tiny seedlings emerging in early spring in a deep purple color. As the vigorous plants grow, the foliage color softens to reddish purple. Then by midsummer, at a height of 5 feet, this wonderful plant adds a vertical accent. Its insignificant flowers mature into beautiful seed stalks by autumn. I like to leave some for winter interest; the birds like them, too.
With self-sowers, seedlings spring up where you least expect them. Not only do they fill gaps in borders, they also provide fantastic plant combinations. One self-sower that blooms early in my garden, bronze-leaved corydalis (Corydalis ophiocarpa), appeared last spring amid dusky, dark-purple ‘Queen of Night’ tulips. Its soft, maroon-tinged, yellow flowers contrasted wonderfully with the tulips. A patch of bronze fennel (Foeniculum vulgare ‘Purpureum’) also grew nearby; its purple-hued foliage provided a rich backdrop for the velvety tulip blooms.
Other self-sowers give exclamation points to the garden. In its second year, biennial clary sage (Salvia sclarea var. turkestanica) sends up stately spikes with lovely pinkish-white flowers. Similarly, spiny plume thistle (Cirsium spinosissimum) emerges from a tight, variegated rosette into bold stalks topped with spiny, purple blossoms. Both add drama and excitement to beds.