Certain plants take center stage as summer wanes, no matter where you live and what you define as summer. Whether you garden in a temperate climate with cold winters (most of Western New York) or in milder maritime zones (much of Ireland or England for instance), the late summer gardens have certain characteristics.
Flowering perennials are generally taller than spring bloomers. Plants that have finished flowering tend to produce new foliage at their crowns, and some produce large and colorful leaves to finish out the season. Berries and seeds are more visible and prevalent, as late-season plants serve pollinators and birds with nutrition for the winter. True annuals, as if knowing it’s their last performance, are large and full of flowers or masses of seeds. A September garden is just different from the June version.
Buffalo or Dublin
I recently compared late August gardens around Dublin and southeastern Ireland with the gardens of Western New York. In that part of Ireland summers tend to remain between 60 to 80 degrees (similar to our area) but winters average in the 40s and 50s with only rare dips below freezing. Snow is rare. As a result, the gardeners grow most of the same perennials, shrubs and trees that are popular here. But they also use tropical plants lavishly – many of them left outside in the soil or in containers for the winter.
Perennials that require a cold period to reboot for spring, such as hostas, were obviously healthy, but plants that can’t take severe freezing were also thriving.
How envious this Buffalonian felt upon seeing a 5-foot New Zealand flax (Phormium) planted in a permanent position outside: beige, cream and eggplant colored striped leaves next to yellow roses! Bananas were also long term outdoor residents of those gardens, adding intense drama when juxtaposed with a planting of Solidago (goldenrod) or Crocosmia ‘Lucifer.’
Most surprising to me was the discovery that fuchsias (just like the little hanging basket plant you grow on the porch to attract the hummingbirds) are spreading freely in gardens and in open fields. No fuchsia will ever see winter in Buffalo.
Another difference among regions or countries is which plants are grown purposefully that we treat as weeds or invasives. My fellow travelers noticed a methodical planting of some kind of pink flowering knotweed or Persicaria outside a restaurant, and we all said, “That’s a weed! I’d be pulling that!”
There are many kinds of Persicaria, commonly called knotweeds or smartweeds. They are all in the family Polygonaceae, the name in Latin referring to “many feet.” Get it? They are mostly vigorous spreaders, using rhizomes or stolons. I own a Persicaria microcephala ‘Red Dragon’ for instance, that has beautiful patterned pointy leaves, controllable because I cut off the flowers every year.
Similarly, the common goldenrod that many people here scorn is a much used perennial in Europe.
An invasive plant in one country is not necessarily a problem in another – in part because plants in their native habitats have native natural enemies – insects or mammals that eat them, or other plants that compete against them well. Ailanthus, Tree of Heaven, is sometimes called the “Tree of Hell” because it is such an invasive, roadside plant causing huge highway department expense to remove it. (It was the famous tough tree in Betty Smith’s classic novel “A Tree Grows in Brooklyn.”)
In America it must be eradicated. In Ireland it is featured at the National Botanical Garden as a 150-year-old specimen near the entrance. Purple loosestrife (Lythrum salicaria) is appropriately listed as a serious invasive plant in much of the U.S., but it is apparently tolerated and sometimes cultivated in Europe and even Canada.
Trees also revealed the climate difference between Ireland and the northeast United States. I saw many examples of Parrotia persica (Parrotia), Laburnum (Golden Chain Tree), Koelreuteria (Golden Rain Tree), Acer griseum (Paperbark Maple), Cercis Canadensis (Redbud) and many of the most delicate Japanese maples – all completely exposed to wind, with no indication of any stress ever.
Those trees are considered hardy in Western New York, mostly, but professional nursery folk usually recommend “some winter protection.” In other words they are usually hardy but sometimes will die after a severely cold winter or a rapid freeze/thaw cycle.
The other big difference was truly that – how big plants grow in a milder zone, compared to our USDA Zone 5 or 6 climate. Japanese anemones were 5 feet tall compared to my own at about 3 feet. Tree peonies – some recognizable cultivars – were at least 18 inches taller than their sisters at home. Woody plants that tend to die back to the ground over winter here, such as Buddleia (butterfly bush), Caryopteris (Bluebeard) and hardy hibiscus, apparently produce their leaves and flowers on stems well above ground. They don’t die back so they can grow much taller in warmer sites.
Phlox, salvias, coneflowers and sedums were present but mostly bigger than we usually see them.
Having noted the differences in two regions’ gardens, I’ll reiterate that late season gardens have a lot in common. The drama comes from the tall plants in full flower: hydrangeas, especially H. paniculata (the taller ones with mostly pointy flowers that bloom in midsummer), the huge Rudbeckias, Joe-Pye weed and buddleias.
Holly species, of different varieties, are sprouting red or black berries in both countries. A beautiful purple-berried Callicarpa in a private Irish garden looked very much like my own at home. The birds, bees and butterflies include many different species but they all need end-of-season pollen and food. Late summer and fall plants seem to know just how to provide what is needed.
In most seasons and in most ways our gardens, at least in temperate climates, are much more alike than they are different.
Sally Cunningham is a garden writer, lecturer and consultant.