Updating Foundation Plantings

Our spring project was to revamp the mid-90s landscape that frames the front of our house. The manual work of pulling out the old and replacing with new was straightforward. The planning process, however, was a multi-month task that required many hours of research and collaboration with our landscaper. I hope that sharing our experience will be useful to homeowners who are refreshing, overhauling, or designing from scratch on a new lot. I’ll describe the plants we inherited, what we wanted to change, our goals, and the plant selections that met our criteria.

THE INHERITANCE

As you can see from the photos, the shrubs were packed in very tightly, which is not unusual for a landscape that is almost 30 years old. The very large holly shrubs are most probably American hollies, Ilex opaca, pruned to a round shape. They flank Japanese maple bushes which have obviously outgrown their allotted space in front of the house. To the far right, is a conical-shaped tree holly, probably also an American holly, and a large male American holly bush next to it around the corner. The landscaper assumed the male holly was planted to pollinate the tree-shaped holly, and the other American holly shrubs. We decided to keep the tree holly and the male holly. The flowering shrub is a nonnative viburnum, probably a Japanese snowball. (Although I really liked this nonnative viburnum, it was just too big for the new plantings. Finding the right scale can be a challenge when trying to mix old and new shrubs.) On the left, in the front corner, is a crepe myrtle set very close to the house. To the left of the crepe myrtle are two Japanese azaleas. On the far left, out of view, are 5 dwarf nandinas. This sterile cultivar does not flower or produce the bright red berries of Nandina domestica. A small red Japanese maple tree to the left of the nandinas was left in place. There was a 2.5’ wide gardening strip on either side of the front walk. We had planted 2 different types of native sedge (Carex), but that combination never really worked. We decided to eliminate the gardening strip and plant grass up to the edge of the walk. We left in place two dwarf inkberry hollies at the end of the path near the circular drive.

NECESSARY CHANGES

On a practical note, the overgrown hollies, viburnum, and Japanese maples prevented us from reaching the windows for washing, and made access to the dryer vents very difficult. The hollies also required severe pruning to keep the stair railings usable.  In addition, my husband seemed to have a severe reaction from pruning the hollies (beyond just a dislike of pruning) when the hollies touched his skin. He broke out in a serious rash that lasted for a couple of weeks.

WHAT WE HOPED TO ACHIEVE

An overall goal was to incorporate as many native plants as possible. Neither the nandinas, the snowball viburnum, the azaleas, the crepe myrtle, nor the Japanese maples met this criterion. We also wanted to make the foundation plantings complementary to the natural setting, which is open acreage surrounded by hay fields. The desired look would be something looser and more natural looking than the original foundation planting. Proper spacing for the plants was also very important. Providing food and cover for native insects and birds were also goals.

SOIL TESTING

We tested the front and back areas of our lawn area about 3 years ago and the clay soil was acidic, with a pH of 5.5 in the back and 6.0 in the front. Many of the shrubs we chose for the foundation area prefer acidic soils, which seemed like a good fit. Soil samples were taken this fall from both sides of the foundation area to check the pH and nutrient profiles of the new beds. Surprisingly, the right side of the bed has a pH of 7.1 (neutral), while the left side has a pH of 6.1 (slightly acidic). We’ve added aluminum sulfate this fall to lower the pH on the right side. Depending on the health of our shrubs next spring/summer, we may need to retest the soil. See this article for more information on changing the pH of your soil.

SELECTING PLANTS TO ACHIEVE OUR GOALS

We decided to use native evergreen plants as the main foundation plants but there are surprisingly few options. Boxwood is a common foundation plant, but it is not native to North America. There was also a severe case of boxwood blight at our previous location in Charlottesville. In addition to evergreen shrubs, we wanted to add deciduous shrubs for different leaf textures, periods of bloom, and colorful fall foliage.

INKBERRY – Ilex glabra

We chose the native evergreen shrub, inkberry (Ilex glabra), as the anchor shrub for our layout. This species reaches a mature height of 5-10’ and a width of 5-8’. An April 2022 article from The Garden Shed describes some basic challenges with using inkberries. A primary consideration is that inkberries tend to become leggy as they age, meaning that as they grow taller, they tend to lose their bottom branches and look thinned out. Some of the newer inkberry cultivars are supposed to retain fullness better than the straight species, but there are still warnings about thinning out as they age. We chose Ilex glabra ‘Nigra’ for the back of the foundation. ‘Nigra’ has a mature height of 6-10’ which, with some pruning, will keep the shrubs below the windows. For the front row of inkberries, we considered the cultivars ‘Densa’, ‘Shamrock’, or ‘Compacta’ for a fuller, shorter shrub. ‘Densa’ was available, and we were happy with its size of 4-6’ tall and wide. ‘Gembox’ is the dwarf inkberry cultivar we selected for the end of the walk. It grows to about 2-3’ tall and wide.

Both male and female inkberry hollies are required if berries are desired. The flowers are not self-fertile and are pollinated by bees. If pollination occurs between male and female plants, flowers are followed by pea-sized, jet black, berry-like drupes which mature in early fall. These berries are attractive to many songbirds. Although female shrubs are common in nurseries, it is difficult to find male cultivars, or male inkberry straight species. The Holly Society of America noted that some inkberries might have self-fertile flowers, or they may be pollinated by other Ilex species, such as I. opaca. We are hoping that the inherited male I. opaca  will pollinate the female inkberries.

VIRGINIA SWEETSPIRE – Itea

One of the deciduous shrubs we incorporated is Itea ‘Little Henry’, a dwarf cultivar that grows 2-3’ tall and wide. Itea is a low-maintenance shrub recommended for well-drained, moist-to-wet, medium acidic soils with a pH of 5.0 to 6.5.  Usually categorized as a wetland species, Itea can also thrive in average moisture conditions, and can tolerate drought conditions once it becomes established. Although it can adapt to partial sun conditions, it develops a fuller habit, flowers more profusely, and shows more vibrant fall color in full sun. This shrub has three seasons of interest with long, white, sweetly scented flowering “spires” in late May and June; fall foliage in shades of red, orange, and purple; and deep, glossy green foliage in summer. A possible downside is that Itea tends to sucker, i.e., spreads by sending up shoots. Some suckering will be welcomed in our foundation area, and suckering is easily controlled by pruning. For more information on this shrub, see the April 2017 issue of The Garden Shed.

 

FOTHERGILLA

Fothergilla is another native, deciduous shrub that met our selection criteria.  There are only two species of Fothergilla and both are native to the southeastern United States: large Fothergilla (Fothergilla major) and dwarf Fothergilla (Fothergilla gardenii). Large Fothergilla grows 6-10’ tall and 5-9’ wide; dwarf Fothergilla grows to about 3-4’. We chose Fothergilla x intermedia ‘Mount Airy’, a naturally occurring cross between the two species (F. major and F. gardenii).  ‘Mount Airy’ grows about 5’ to 6’ tall and wide and shows consistently good fall colors. In summer, this attractive shrub bears dark green to bluish-green leaves. It is generally thought to be superior to the species in flower size and abundance, cold hardiness, general robustness, and fall color.  Fothergilla thrive in acidic soil with a pH of 5.0-6.0 with plenty of organic matter. It is happy in filtered shade to full sun, but the best fall color is produced in full sun. The dwarf species tends to sucker, and ‘Mount Airy’ tends to sucker as well. For more information on this shrub, see the November 2017 issue of The Garden Shed.

 

 

WILD HYDRANGEA – Hydrangea arborescens

Wild hydrangea or smooth hydrangea grows 7-7.5’ tall and is native to the eastern and central U.S. Although usually found in moist, wooded areas, wild hydrangea can also grow in full sun if provided sufficient water. It has large leaves, and beautiful flower heads that bloom in June and keep blooming for about two months. The flowers then fade to a soft green in early fall, and dry to a tawny brown. The dried flower heads add winter interest to the garden. There are two different types of native hydrangeas: lacecaps and mopheads. Lacecaps have hundreds of fertile flowers usually surrounded by a ring of showy sterile flowers. Mopheads contain masses of sterile flowers in large-dome shaped flowerheads with relatively few fertile flowers. The fertile flowers of lacecaps attract a great number of pollinators, while the sterile flowers of mopheads provide spectacular floral displays. ‘Annabelle’, a simple selection of naturally occurring plants, was one of the earliest wild hydrangeas to exhibit a mophead floral mutation. The cultivar chosen for our foundation plantings is ‘Incrediball’. It was bred from ‘Annabelle’ and is credited with having stronger stems and larger blooms. In fact, ‘Incrediball’ is sometimes called “Strong Annabelle” hydrangea. At 4-5’ tall and wide, the smaller size is suitable for our foundation bed. Many recent cultivar innovations based on selective breeding are mopheads because of the popularity of their exquisite flower displays. The Mt. Cuba Research Center has published a report based on a trial that compared different cultivars of H. arborescens. This study compares overall plant characteristics; the impact of growing in sun versus shade; and attractiveness to pollinators. Wild hydrangeas are subject to severe deer browsing. Although we’re hoping that proximity to the house will provide some protection, we may also need to add plastic fencing for months of heaviest browsing.

OAKLEAF HYDRANGEA – Hydrangea quercifolia

Oakleaf hydrangea is a deciduous, rounded shrub with large, dark green foliage that is lobed, coarsely textured, and similar in shape to the leaf of an oak tree. White flowers appear in elongated, cone-shaped clusters that bloom 4-6 weeks in June-July before aging to either tan or deep pink. The foliage turns a beautiful red to purple and lasts through fall; the dried flowers also add late fall interest. Hydrangeas generally prefer moist, well-drained, acidic soil (5.0-6.5 pH) in partial shade/shade. Once established, the oakleaf species tolerates drier soil and more sun than other members of the genus. Oakleaf hydrangea is native to all the states in the southeastern quadrant of the United States, from North Carolina south to Florida and west to Louisiana. Although not native to Virginia, it performs well here. It is susceptible to significant deer damage; we have planted ours next to the house by the entry. The species grows on average to 8’ tall, with some growing to 12’. There are many cultivars that offer a range of sizes. We selected the compact cultivar ‘Pee Wee’ which grows 4-5’ tall and wide. See the article, “Oakleaf Hydrangea,” from November 2016 issue of The Garden Shed for more information.

MOUNTAIN LAUREL – Kalmia latifolia

Mountain laurel is a broadleaf, evergreen shrub native to eastern North America. In the wild, the species grows 5-15’ tall and wide. We selected a dwarf cultivar, ‘Elf’, that grows 3-4’ tall and wide. Leaves are green and glossy, and clusters of white flowers emerge from distinctive shell pink flower buds in late spring/early summer. Mountain laurel tolerates a wide range of light conditions, from full sun to full shade, but grows best in partial shade (morning sun with early to mid-afternoon shade) and in cool, moist, humus-rich, well-drained, acidic soils. It is subject to chlorosis (yellowing) of the foliage in alkaline soils. Mulching is recommended to retain moisture and keep root zones cool. The species is susceptible to several insects such as borers, scale, white fly, and lace bugs. It is also susceptible to leaf spots and blights. If ingested, all parts of the plant are highly toxic to humans, cats, dogs, and horses. Honeybees that feed heavily on these plants are known to produce “mad honey” that can be toxic for human consumption. Mountain laurel is attractive to many pollinators, including butterflies and hummingbirds. It is usually deer resistant.

 

RED SWITCH GRASS – Panicum virgatum ‘Shenandoah’

We chose to replace the dwarf nandina bushes with a cultivar of the native perennial switch grass, Panicum virgatum. ‘Shenandoah’ grows 3-4’ tall topped in summer by finely textured, reddish-pink flower panicles which hover over the foliage like an airy cloud. Panicles turn beige as the seeds mature in fall with the seed plumes persisting well into winter. Seeds are a winter food source for birds. Foliage emerges bluish green but rapidly turns burgundy red by late June. ‘Shenandoah’ features some of the best burgundy-red foliage of the many panicum cultivars currently available. This warm-season grass tolerates a wide range of soils and is easily grown in average, medium-to-wet soils; it may flop in overly rich soils. It can tolerate both dry soils and occasional flooding. It generally prefers full sun and is planted in the sunniest spot of our foundation bed. It grows primarily in clumps but will slowly spread by slightly creeping rhizomes. Plants may self-seed in optimum growing conditions, but cultivars may not come true from seed. It is not attractive to deer.

SEDGE – Carex

Although not a grass, sedge is a “grass-like” perennial plant with triangular stems and inconspicuous flowers. Of the family Cyperaceae, there are over 1,500 species of the genus Carex, which from Latin means “cutter” in reference to the sharp leaves and stem edges. As a native ground cover, it can reduce the need for mulch and suppress weeds. It is sometimes used in place of turf to reduce lawn maintenance and is also an effective specimen plant in ornamental and rain gardens. Various native sedges act as caterpillar hosts plants for moths and butterflies. While many sedges prefer moist conditions in shade/partial shade, some will tolerate dryer conditions in more sunlight. Prior to our foundation planting project, we had included two different types of sedges along our front walk, a dry area with 5-6 hours of full sun. Blue wood sedge (C. flaccosperma) grew very full but tended to turn brown as the summer wore on. The second sedge, Pennsylvania sedge (C. pensylvanica), was better able to withstand the sunny, dry conditions. Although both types would probably be happier with more shade, we decided to transplant C. penslvanica into the foundation bed to act as a ground cover to reduce the need for mulch, and to provide food and cover for native insects. It has adapted well and has not been bothered by deer. For more information, also see this article in the June 2019 issue of The Garden Shed.

PLANTS NATIVE TO VIRGINIA

Many gardeners are now aware of using plants not just native to North America, or even to a region, but to areas more specific to locally defined areas. Inkberry (Ilex glabra), American holly (Ilex opaca), Virginia sweetspire (Itea virginica), smooth or wild hydrangea (Hydrangea arborescens), switch grass (Panicum virgatum), mountain laurel (Kalmia latifolia), Pennsylvania sedge (Carex pensylvanica), and blue wood sedge (C. flaccosperma) are all native to Albemarle County. See the Piedmont Virginia Native Plant Database.

DWARF OR COMPACT SHRUBS

Although our goal was to include native plants, many of the native shrubs we chose grow quite large at maturity. This meant that dwarf varieties were a welcomed addition. We chose cultivars that kept the green-colored foliage of the species, since work by Doug Tallamy has shown that the burgundy, purple, and other colored foliage of cultivars may not be as attractive to native caterpillars. For more information on compact cultivars, see this article in the October 2022 issue of The Garden Shed.

SUMMARY

Our goal was to change an out-of-date, overgrown foundation bed into an attractive, native-plant-based design that would also be productive. Productive means that the plants would support native insects, act as larval hosts to native moths and butterflies, and provide rich sources of nectar and pollen. The landscape would also provide food and cover for birds and other wildlife. Of course, we also wanted to create a beautiful setting for our home that would highlight the natural features of our landscape and beckon us outside.

FEATURED PHOTO Panicum virgatum ‘Shenandoah’ planted in place of dwarf nandinas. Photo: Susan Martin

SOURCES

“Inkberry—A Native Evergreen Shrub,” The Garden Shed, April 2022.

“Inkberry Holly,” University of Maryland Extension.

“Virginia Sweetspire,” The Garden Shed, June 2017.

“Fothergilla – An Outstanding Choice for Fall Color,” The Garden Shed, November 2017.

Albemarle County Native Plant Search

“Wild Hydrangea for the Mid-Atlantic Region,” Mt. Cuba Center Research Report

“Oakleaf hydrangea,” The Garden Shed, November 2016

“Kalmia latifolia,” NC State Extension

“Panicum Virgatum,” NC State Extension

“The Sedge Alternative,” The Garden Shed, June 2019

“Compact Versions of Commonly Grown Trees and Shrubs,” The Garden Shed, October 2022

“Changing the PH of Your Soil,” Clemson Cooperative Extension

Ladybird Johnson Wildflower Center, Native Plants Database