Transform an overflowing flowerbed or a jam-packed patch of perennials into a landscape with show-stopping curb appeal.
By Jo Ann Gardner
In Buffalo, New York, a narrow yard is filled to the brim with shade-loving hostas—a perennial that's lush whether it's in bloom or not. (Photo: Anthony Fracasso)
You may be lucky enough to buy an old house with an established garden to match. That could become the starting point of a beautiful landscape, but the surviving plants might be a mixed blessing.
How do you deal with overgrown carpets of goutweed that defy pruning? What’s to be done with crowded lilacs? And what about sprawling mats of iris that show promise but barely bud? Should you remove these plants and shrubs, or coax them into bloom by ruthless trimming, reducing, and dividing?
The best approach is not to be hasty. If you dig up the garden prematurely, you may unwittingly destroy bulbs or a desirable heirloom plant that was less noticeable than its more vigorous neighbors. Be especially prudent when removing trees or shrubs, since they take years, even decades, to grow to maturity.
During the first season you spend with your inherited garden, observe what’s growing from early spring through autumn, and record what you see. Draw a rough diagram of the garden, recording location, bloom time, color, and names (if possible) of all the plants. In the fall, spread a thick, nutrient-rich organic mulch, such as rotted manure or compost, over the entire garden. This will help soften the soil and make weeding and dividing much easier come spring.
If you’re having difficulty deciding what to save and what to discard, take care not to throw out common plants, because they may prove useful somewhere else on your property. Robust survivors, like the common orange daylily (Hemerocallis fulva) and hostas, for instance, have potential as ground covers where little else will grow. Cream-variegated goutweed (Aegopodium podagraria ‘Variegatum’) can light up a dark corner or make an eye-catching hedge if kept mown on both sides. Just as you lovingly restore and preserve the history of your old house, it’s wise to take the same level of care to the land on which it sits. A thoughtful plan will help you to create a satisfying new garden from the remnants of the old.
Goutweed propagates quickly—12 roots will cover about 10 square feet in just two seasons. Mow down flowering stalks in early spring, and mow around the area to contain growth. To get rid of the less ornamental green goutweed, spray with Round-Up for three successive seasons.
Excellent for holding soil on steep banks. Pull apart large clumps of tubers, discarding old ones. Set selected tubers 18″ to 24″ apart, with their crowns 1″ below the soil’s surface.
Dig up roots in late spring, as soon as new growth appears. Set divisions out, with the juncture of roots and leaves at ground level. Space them according to their expected full growth: 3′ apart for large-leafed types and 8″ to 12″ apart for smaller-leafed types.
Siberian iris and old yellow flag iris (Iris pseudacorus) prefer moist soil; bearded iris needs well-drained, lighter soil. To divide clumps, dig up after flowering, shake off soil, and remove two-thirds of the foliage. Select two small rhizomes (surface roots) growing at an angle from the large one, cut them with a sharp knife, and reset them in soil 6″ to 8″ apart. Discard all hard parts.
If blooms are sparse, dig up and replant after leaves turn brown. Store bulbs in a dry place through the summer, then replant them in the fall. Planting depth should be two to three times the height of the bulb, allowing five large or seven to 10 small bulbs per square foot. Add a teaspoon of bone meal to each planting hole if desired.
If old clumps are doing well, leave them alone. If you want more roots for a hedge or for another site, replant roots with three to five buds (or eyes) in rich, slightly acidic soil during fall. The planting hole should be deep enough to comfortably accommodate roots, but the tops of the buds should be no more than 2″ below the surface. Add a handful of bone meal to the planting hole. Note: It may take three seasons for plants to produce abundant blooms.
Ribbon grass has tenacious, wide-spreading roots. Space plants 6″ to 12″ apart to establish as a ground cover, or plant three or four roots in a large drainpipe or bucket sunk into the ground to control root spread. Cut down flowering stalks in summer.
Old survivors are often harsh magenta shades, but some of these may be salvageable. Select the best colors, and discard any plants noticeably afflicted with whitish powdery mildew late in the season. Space plants 18″ apart and divide clumps every four or five years. Cut back spent flowers before they form seeds to avoid seedlings of undesired color.
Observe carefully any surviving roses to find out if they’re worth keeping. To improve the condition of older, established roses, prune after they bloom; if the variety is a repeat bloomer, cut back hard in spring. When pruning, cut out all crossed, very old, or dead branches; any extra growth in the middle of the plant; and pencil-sized stems. If stems and branches are very thick and thorny, the rose may be undesirable understock, and should be discarded. The plant will thrive better in uncrowded conditions.
Almost any soil, except soggy, works well for lilacs. To revive overgrown specimens, follow this formula: The first season after they bloom, cut out one-third of the largest, oldest stems and thin out the small shoots; the second season, cut out another third; the third season, remove the last third. This will gradually reduce the shrub’s height without sacrificing its blooming potential.
Photo credits: Goutweed, iris, peony, ribbon grass: Perennialresource.com; Ditch lily, hosta, border phlox, rose: Pine Photography; Daffodil, lilac: Toni Smith Published in: Old-House Journal November/December 2008