Dont mistake treasures for intruders
Recently when a friend visited my garden she was amazed at how many hellebores were in bloom. I told her how I'd started with a dozen or so plants, mostly grown from seed, back in the 1980s, and then I just let the mature plants self sow.
'Why don't mine do that?' she wondered.
'Are you deadheading the spent flowers?' I asked.
Turned out that she had removed the faded flowers before they had a chance to form seedpods. Uh-oh! If you want more hellebores, it's best to wait.
You have to accept a less tidy look - the old flowers lose their glamor, as they age and turn pale. But hellebores especially are worth letting go until seed capsules form at the centers of the flowers in spring. Eventually, the pods turn papery, then explode; small black seeds will scatter near the mother plant and baby hellebores will germinate.
I encourage this by mulching with compost around the hellebores in spring, so that the seeds fall on fertile ground. After years of allowing the hellebores to be fruitful and multiply, I've transplanted seedlings here and there so that winter color is sprinkled throughout the garden.
I know that some gardeners are very picky about pure colors, as well as interesting markings, but I don't mind the mixture that results from this open pollination - actually it's fun to see the surprising array of pink, white, wine, cream and speckled flowers.
Beyond hellebores, lots more perennials and annuals multiply this way. It's a shame to weed out treasures, mistaking them for intruders. Fortunately, it's not that difficult to learn to recognize who's who: Begin by studying the shape of the mother plant's leaves, then look for miniature versions springing up after bloom period.
Love-in-a-mist is one of my favorite annuals that self-sows - blue, pink or white flowers bloom above finely dissected leaves. The seedlings are light green and feathery as fennel. After the flowers bloom in summer, let the puffy balloon-shaped seedpods ripen to bursting - soft, ferny-looking seedlings will emerge the next spring.
I have a love-hate relationship with columbine, which flings itself near and far. I never know where it will spring up - at the front of a bed, splat in the middle of another perennial or in a sidewalk crack. It can be charming or annoying, depending on where the seeds germinate. Curiosity almost always makes me wait until it blooms before I keep it or dig it out, as the colors are so diverse - pink, purple, yellow, orange, white, blue and sometimes bicolored. When the leaves turn yellow, I snip them off. New leaves are distinctively rounded.
I adore 'Ravenswing' cow parsley (Anthriscus sylvestris) for its finely incised burgundy foliage and umbels of pink flowers in early summer. It associates so well with companions that I cherish it wherever it lands, sometimes even in a container. Seedlings emerge green to merlot. I cull out the green in favor of the sultrier shades.
Purple angelica (Angelica stricta purpurea) is more dramatic, with similarly dissected but even darker leaves, and deep pink flowers. I've heard gardeners complain that it spreads too much, and very likely the richer your soil the more self-sowers like this will take over. As with 'Ravenswing,' I dig out green seedlings and keep the burgundy ones.
Flowering onions are another story. Some - such as white Allium neapolitanum and yellow Allium molly, both low-growing - seed downward like grass. So beware, unless you want a vast colony. Others - such as Allium multibulbosum and 'Purple Sensation,' both lovely at the middle of a border - spread moderately. I can't get enough of these beauties.
If you're looking for upright flower spikes, consider toadflax (Linaria purpurea) and foxglove (Digitalis purpurea). You'll know toadflax seedlings by their gray-green leaves that resemble lavender. The narrow stems bear abundant lavender flowers, magnets for bees and butterflies. Because they're narrow and filmy, they're perfect filler between shrubs, especially roses, or between lilies, dahlias and daylilies. It's easy to pull out the extras; simply deadhead the flowers if you don't want them to self sow.
Foxglove's furry rosettes makes it easy to spot in the garden. I let them bloom anywhere they land, as the bees love them so. I get a kick out of watching bumblebees work their way down the center of foxglove flowers, wiggling their little rumps as they feast.
• Hardy Plant Society of Oregon's Spring Plant Sale and Garden Festival, 10 a.m. to 3 p.m., April 17 and 18, Portland Expo Center, 2060 N. Marine Drive, Portland. Free admission, parking $7 each car, $6 carpools of three or more. For complete information visit www.hardyplantsociety.org."
• Leach Garden Friends 2010 Spring Plant Sale, 9 a.m. to 3 p.m., April 24, Floyd Light Middle School, 10800 S.E. Washington St. (near Mall 205). Admission and parking are free. For more information, visit www.LeachGarden.org or call Katie at 503-761-4751.