On September 20th, I gave an evening talk free to HSNY members on a number of reliable plants for city gardens. The talk was part of HSNY's educational programming in horticulture. It consisted of 20 plants that we have had good experiences with at our GreenBranches Learning Gardens, not to mention a few others that I have seen do very well in urban gardens throughout New York City. For my talk I mostly used photographs from HSNY gardens. However, I also visited my alma mater, the New York Botanical Garden, so that I could photograph a few specific cultivars to show that within a species you can find many options. Here a few of those plants:Sedum 'Autumn Joy' is a sun loving, drought tolerant 2' perennial with spectacular clusters of star shaped pink flowers late summer. It is often followed by attractive fall color.
Heuchera cultivars come in many different colors, from green to maroon to purple to silver and combinations thereof. This is Heuchera 'Pewter Veil' planted under a small tree in part shade. This mounding 12"-18" perennial I love as an edging plant or mixed with low-growing grasses to provide contrast in the garden.
Yucca filamentosa is a North American native and adds instant 2'+ structure to either a perennial or annual display. Since it is so spiky I usually mix it with hot colors like yellows, reds, and oranges. When I worked for the New England Wild Flower Society there was an all-native planting of Yucca filamentosa, prickly pear cactus (Opuntia humifusa), and black-eyed Susan (Rudbeckia sp.) that I absolutely fell in love with. Two final words on Yucca: drought tolerant.
Heuchera 'Amethyst Mist' and variegated Adam's needle, Yucca filamentosa 'Variegata'.
Hakonechloa macra 'All Gold' is a more yellow form of the classic Hakonechloa macra 'Aureola', commonly called Japanese forest grass or sometimes hack grass. A great low, spreading grass that tolerates a little shade and mixes well with many groundcovers and mounded perennials.
Nepeta sp. is called catmint, and the foliage when crushed is quite fragrant. Pinch this mounding perennial back throughout the spring and summer and you end up with a full bushy plant with excellent fine leaf texture that blooms repeatedly all summer long.
Cotinus coggygria 'Royal Purple' puts out new stems and foliage that in full sun are spectacular. An excellent upright woody shrub for foundations or alone in the landscape, smokebush puts up a light plume of flowers mid- to late-summer that resembles a cloud of smoke.
Common crapemyrtles, Lagerstroemia indica, grow their foliage and late-summer flower clusters on top of long trunks that are exceptional for their structural look and bark texture. Crapemyrtle cultivars can be classified by overall size, flower color, trunk color, and fall color. Talk about options! And as global warming makes our winters more and more mild, these attractive trees from down south are slowly showing their viability in New York City. I even know of an estate manager creating his own hybrids that are tolerant of salt spray coming off Long Island Sound. Lagerstroemia indica 'Choctaw', photographed above, is a tall tree to 33', with clear bright pink flowers, light to dark cinnamon brown bark, and bronze-maroon fall color.
Cornus sericea is commonly called redosier dogwood. Planted in full sun this woody shrub can grow to 6'-8'. The new growth comes out a bright fire engine red, an extra color element in the winter landscape especially. I also like in spring when the new leaves are more chartreuse and contrasting the bright red stems. I would take selective branches and cut them back hard every couple of years to keep that red new growth coming back.
Cercis canadensis is another North American native that is a favorite small tree of mine. The bright pink/magenta flowers that bloom right on the dark stems in spring followed by heart-shaped leaves make it a great tree option for small city gardens. I'd plant this tree in a sunny protected courtyard in a second. The culivar 'Forest Pansy' has new growth that is more red and matures green as the tree ages, granted it is in full sun.
Most people know the glossy pachysandra that is all over the city, Pachysandra terminalis, but the above plant, Pachysandra procumbens, is the North American native alternative to the glossy form. Whether it is classified as being simply "aggresive" or more seriously "invasive", I'm not a huge fan of Pachysandra terminalis because it can easily take over other plants in the garden if left unattended. Therefore, I like the larger leaf and more mat-finish of Pachysandra procumbens which still spreads well in part shade and has similar clusters of sweet white flowers in early spring.