Thomas Rainer's advice on selecting plants

"Nature should be interpreted, not imitated in designed landscapes."

~Thomas Rainer"

Thomas Rainer, who has designed landscapes for designed landscapes for the The New York Botanical Garden, U.S. Capitol grounds, the Martin Luther King, Jr. Memorial, and many other gardens, offers some guidance on the debate over natives vs. exotics that provides a reasonable approach to this dilemma for me. 

According to Thomas Rainer, "some of the best plantsmen in the world achieve success in part through discriminating taste in plant selection. They seek out not only the most vigorous plants, but also the most interesting selections. This discerning eye is one of the qualities that unite a diverse group of plantsmen such as Karl Foerster, Mien Ruys, Beth Chatto, Wolfgang Oehme, Henk Gerritson, Piet Oudolf, Fergus Garrett, Dan Hinkley, and Roy Diblik. Their gardens are legendary in part because of their ruthlessness in plant selection. And as a result, they made us see their plants (and gardens) in a new light."

So who are these plantsmen whose ruthless selection of plants so impressed Rainer?

While Karl Foerster is best known for breeding Calamagrostis x acutiflora 'Karl Foerster' grass, his design work is credited with greatly influencing the New German style of planting and the naturalistic planting movements that have since followed.  He experimented with a naturalistic planting style by combining grasses and massed perennials to achieve an overall meadow effect.

Karl Foerster's garden in Potsdam-Bornim, Germany.

Mien Ruys' use of loose natural plantings surrounding a space and the emphasis on the perennial borders differentiated her designs from those of her peers at the time. She believed perennials allowed an individual to interact and have a direct experience with nature.

Mien Ruys garden in the Netherlands

A sign at the entrance to Beth Chatto's gravel garden reads: "The Gravel Garden is not irrigated. It is a horticultural experiment where we hope to learn which plants survive extreme conditions, as a help to all gardeners facing hosepipe bans."

Beth Chatto's Gravel Garden in 

Wolfgang Oehme's partnership with James van Sweden,  in the Washington, D.C. firm, Oehme, van Sweden & Associates, Inc. (OvS), grew to encompass architecture, landscape architecture, and urban design. Their first major commission in 1977 was the Virginia Avenue gardens for the Federal Reserve in Washington, D.C. The design of these gardens broke with the traditional federal garden palette and launched a new garden style known as the ‘New American Garden.’ Their signature style makes use of large prairie-style drifts of grasses and herbaceous plant material used in a painterly fashion to create a diversity of form and color in the garden and highlight the seasonal aspects of the plants. The firm is credited with changing the face of landscape architecture in the U.S. by introducing the idea of replacing the lawn with naturalistic, low-maintenance, multi-seasonal plantings.

Federal Reserve garden

Henk Gerritsen and Piet Oudolf, who co-authored a number of books planting "the natural garden", are widely credited with starting the "Dutch Wave," a movement that is now sweeping gardens from Europe to North America. The authors emphasize how gardeners can create moods and emotional responses through the use of themed plants, chosen their plants for hardiness and suitability for garden habitats.  

 Kaatje's Garden in the Priona Gardens by Henk Gerritsen and Anton Schlepers.
  Though formal by layout, the garden is rather a satire on the formal garden.

Piet Oudolf's work has inspired an “ecology meets design” New Wave Planting movement. His work in Germany  hybridizing and closely studying plant behavior and characteristics, has given him an uncanny ability to compose a garden where the plants work well together year round, throughout the phases of birth, life and death.He has done the planting design for gardens in Millennium Park in Chicago, the Battery in New York, and the elevated High Line rail bed in Lower Manhattan.

The High Line, New York City

Fergus Garrett, Christopher Lloyd's head gardener at the Great Dixter for the last 15 years of his life, took charge of the house and garden upon his death.  Garrett continues the working method laid down by Christopher Lloyd consisting of a daily perambulation around the garden during which they  would consider whether plants grow were growing well and whether they could stand on their own.  But he is also allowing his own horticultural voice to sing out, especially in an emphasis on "link plants".

Fergus Garrett's deep understanding of the Great Dixter led Christopher Lloyd
 to choose him to  ensure the preservation of his dynamic estate
where experimentation has always been a defining characteristic.

Dan Hinkley has methodically looked for new plants for temperate gardens for the over 25 years, both in the Northern and Southern Hemispheres. His observations of these plants in their natural ecosystems have allowed Dan to promote their use in specific landscape applications in North America. After rigorous governmental inspection and systematic evaluation to insure his introductions will not pose a threat through bio-invasion, plants are released for the enjoyment of gardeners across our country.

Dan Hinkley and partner Robert Jones' Windcliff, with an extreme exposure
 to both sun and wind; yet, relatively free of frost, since cold winter air
merely drains off the cliff to the beach far below (Sunset zone 5).

Noted plants man and designer Roy Diblik is best known as the plants man behind Piet Oudolf's Midwestern garden designs, including the Lurie Garden at Millennium Park in Chicago.The plants in Roy Diblik's gardens at Northwind Perennial Farm have been so carefully chosen to live well together that they rarely compete. Diblik advocates a "Know Maintenance Approach" to reduce weeding, fertilizing and watering.   Roy's suggestions: make maintenance a priority, think long-term, limit the number of species, learn about the qualities of each species in combination as you divide and recombine them, think in communities, expect reseeding, plan for weeding, grow lush, thick plantings to reduce weeds, and when cutting plants back in March let the cut up the dried stalks and leaves fall to the ground to decay and feed the plants as an alternative to buying wood-chip mulch.

Roy Diblik's plantings at Northwind Perennial Farm in Burlington, WI

Thomas Rainer's suggestions for selecting plants :

1. Take a hike.  See plants growing in their community of origin.  Understanding the culture of a plant, can help inspire you to expand your palette of plants and create  new combinations.
2. Go hunting: Learn how to propagate your own plants from seed or cuttings.  While mail ordering from specialty nurseries increases your options, it can be very expensive. Trading plants with other adventurous gardeners is another way to obtain great plants. Seed exchanges offered through horticultural societies often offer many rare and unusual selections. 
3.  Don’t be dogmatic about native/exotic, straight species/cultivar.  What makes a garden-worthy plant is not the plant’s pedigree, but its performance.  "We would rather have a vigorous monarda in our natural garden, produced through a lengthy selection process (in other words, cultivated), than a wild specimen which degenerates into a pathetic pile of mildew in our climate.” ~Oudolf and Gerritsen
4. Look at the plant lists, not the glossy pictures.   Great plants men often have a “palette” they use frequently, so some of their most used cultivars are likely all-star performers worth trying in your own garden. 
5. Trial the plant yourself.   Garden knowledge comes from propagating, growing, and testing a plant in multiple places. Knowing a plant’s tolerance gives you the confidence to plant boldly and take risks.
6. Form, texture, and resiliency trump flower color. Sometimes plants qualities become more apparent when viewed in combination with other plants. 
7. Follow the best breeders.  Thomas recommends Dan Hinkley, Dan Heims of Terra Nova, Steve Castorani of North Creek Nurseries, Roy Diblik of Northwind Perennial Farm as a few of the American breeders worth watching. 
8. Don’t be snobby about widely used plants, just selective.  A great plantsmen can make a common plant look interesting by combining it with other plants in new and interesting ways.