I never thought I would see a good example of using exclusively annuals like one would use perennials in border design. When I first looked at the trial garden beds, the view “read” perennial. Upon closer inspection, the beds were filled with drifts of many tall annuals. It read differently because of the height of the plants and how the plants worked so seamlessly together.
Additionally, the trial gardens were neighboring the Idea Garden, showing innovative pairings of plant varieties that could be used reliably in gardens in the Eastern Pennsylvania area. They used selections for beds of annuals, perennials, vegetables, and small fruit to provide inspiration for the viewer. The 5 acre Idea Garden was formally the vegetable garden for the estate. Check out the images and see what could work for you!
The trials help determine plant combinations for the main display beds. I found this somewhat surprising considering the care of planting and design using color, texture and massing. Longwood staff does research and plant evaluation processes putting the newer variety annuals to the test. All are evaluated every two weeks to see if they cut the mustard for future display.
This garden was formally dedicated to groundcovers, vines, ornamental grasses, and roses.
I viewed the gardens as a final vignette, or finished border. On this trip I was asked what we could learn from this and I offered substituting the annuals with similar color, size and texture of perennials.
The average gardener could not replicate these costly designs because many plants are raised to almost maturity in the winter greenhouses, then planted outside full and healthy. Where one might plant Coleus or Caladium, Heuchera or bright Hosta would be a nice substitution, or just use the easy to find, inexpensive tender annuals, but start them early indoors.
Tropical big leaved Colacasia, Alocasia, 7-foot cannas and banana just need big leaved perennials to give that feel of the tropics. Gunnera, Verbascum, Rodgersia, Crambe, Darmera peltata, Hosta, Ligularia, Mayapple, Brunnera, Petasites japonicus, are all hardy plants with large leaves. I can’t think of any with the height and elongated form of banana or Elephant Ears, but these choices are great for substitution.
The flowers are a bit easier to find plants of similar qualities, even tall varieties. Some include Agastache, Asclepias, Bear Breeches, Monkshead, Japanese Anemone, Cardoon, Asters, Delphinium, Foxglove, Globe Thistle, Sea Holly, and of course, self-seeding annuals like Cleome, Cosmos, Verbena bonariensis (7b), Tithonia (8b), and more. The list of tall flowers is long.
Many hardy grasses can be used as well. Cyperus papyrus ‘King Tut’ (zone 9-10) is shown in these beds and is a tropical tall sedge. Cortaderia selloana ‘Pampas Grass’ also has showy flowers and may be hardy in zone 7 with a heavy mulch. Other Erianthus are hardy to zone 4, just a bit aggressive in the garden.
Silver leaves are not a hard substitution either, but substitution for pointy, leathery or sharp succulents takes a bit of thought. Yucca or Prickly Pear are plants used in our region. Take a look through the gallery images and add your hardy design substitutions. Like I mentioned to folks on the trip, cold region gardens have quite a few similar choices.
See the Lily Pools at Longwood Gardens on Nature and Wildlife Pics. So beautiful in August.