Stuck at Home? Time to Garden

A continuation of last month’s column, “Selecting Plants for Wet Shade”

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In the late fall of 2018, I visited a 10-acre property in Eads with a beautiful French Tudor home constructed at the highest point. But there was a lovely field in a low spot next to Raleigh-Lagrange Road where all the rain collected. Some of the water percolated into the large flat area of about 2,500 square feet, sitting in the natural indentations. Much of it flowed under the road through a large concrete pipe. Three Betula nigra (River Birch trees) in a triangular formation shaded part of the low area. A large Nyssa sylvatica, one of my favorite trees, a tree native to the swamps of Mississippi, shaded the rest of it.

Earlier owners had built a small guest house overlooking this area. Deer, rabbit, and many birds frequent the area. The animals could be seen congregating sometimes from the large picture window of the somewhat dilapidated but soon to be repaired guest house.

The owners had other landscapers plant things like Camellia japonica, hybrids of Rhododendron indica, Hosta, and other standard shade plants. All these failed. They did not necessarily die completely but those that lived failed to grow much, had yellowing leaves, and seemed to struggle with pest problems.

The owners even had part of the area sodded in Zoysia turf grass three times, reasoning that it was a shade grass. The last landscaper, bizarrely, recommended they try a newer hybrid of Zoysia called Palisades, because it needs less light than the older Zoysia Meyers. Of course, the irony of this is that Palisades is also more prone to root rot in excess moisture. Thus, it failed even more quickly than the Zoysia Meyers turfgrass had.

So, the core issue is simply that they had been considering light conditions in the selection of plants, but they had not been considering soil moisture level as a limiting factor. Some plant species evolved to resist root rot and other problems associated with wetter soils better. These are known among horticulturalists as “plants that tolerate wet feet well.”

Last month, I introduced the topic of wet shade. I promised to discuss some of the plants that do well despite these two limiting factors of low light and excess moisture. Accordingly, here are six of the many I used in my successful design for these clients, plants that are now thriving in the area I described.

1.  Acorus gramineus ‘Hakuro-nishiki’ (Dwarf Golden Sweet Flag - above)

There are several cultivars of Acorus gramineus in the nursery trade. I am particularly partial to ‘Hakuro-nishiki’ also called ‘Minimus aureus’. It is reliably evergreen in Memphis. This plant is not native to the United States.

2. Distylium

Distylium is a genus that includes multiple species, all of which have done well for me in part shade with chronically moist soil. Dr. Michael Dirr, a horticulture professor at the University of Georgia, professional plant explorer, and professional plant breeder, has brought a variety of cultivars and hybrids from this genus to the market in the past few years. This evergreen is a relative newcomer to the nursery trade.

Cultivars of Distylium that have served me well in designs include 2-A ‘Cinnamon Girl’, 2-B ‘‘Emerald Heights’, 2-C ‘Blue Cascade’, ‘Coppertone’, Vintage Jade’, and ‘Linebacker’. These cultivars vary in height, leaf size and shape, and leaf color. Members of this genus often, though not reliably, produce small red flowers in winter. This plant is not native to the United States.

3. Lobelia cardinalis (Cardinal Flower)

Cardinal flower is an herbaceous perennial, meaning that it dies to the ground in winter and re-emerges in the summer. It has beautiful red blooms. This plant is native to the United States.

4. Tricyrtis hirta (Japanese Toad Lily)

These plants are best known for their incredibly unique flowers, white covered in purple spots. They are herbaceous perennials good for part shade or deep shade.

While Japanese Toad Lily handles moist soil well, it probably could not handle as much constant moisture as a plant like sweet flag. So, it might not be the right plant where there is standing water for long periods of time or water-logged silt so dense that it has become anerobic. This plant is not native to the United States.

5. Hibiscus coccineus (Scarlet Rose Mallow, Swamp Hibiscus)

If you want to add a bit of red pizazz to a part-shade area from the middle to the end of summer, this is the plant! It can handle the wettest soil and even flooding for brief periods. It grows 3-6 feet tall and 2-3 feet wide. This plant is native to the United States.

6. Illicium parviflorum (Small Anise Tree, Yellow Anise, Hardy Anise)

This large evergreen shrub handles very wet conditions in part shade to full shade (full shade is less than 4 hours of sunlight) perfectly. Though it blooms early to mid-summer, I primarily include it in landscape designs for its foliage. It has beautiful yellow tinted leaves that smell a bit like licorice when crushed. It matures at a height of ten to fifteen feet and a width of six to ten feet. Hardy Anise is native to Florida.

There are many more plants for wet shade. If you are looking for a plant recommendation for particular site conditions, email me. You might also join the Facebook group “Mid-South Gardening in USDA Zones 6, 7, & 8.” The administrator of the site keeps downloadable lists in Excel format of plants for various site conditions.

John A. Jennings is an experienced garden designer, garden writer, and nursery manager. He also has degrees from the University of Richmond and the University of Memphis. Email him at gardener@memphismagazine.com.