Trees, Shrubs and Vines for Clay Soil

In the table below are "woodies" that perform very well in clay soil in our area. The table includes the basic information needed to help you site these plants properly. It also includes information on deer resistance and rabbit resistance. So far, I haven't seen deer in my garden and the deer information is from various sources that I have collected over the years. The rabbit resistance information is based on my own garden experience as I always find plenty of rabbits in my garden. Here's how to interpret the information:

• For both Deer Resistant and Rabbit Resistant headings:
  • yes - the plant is not usually eaten. It's possible, though, in some years the pest may eat the plant.
  • no info - there is no definite statement as to the plant's resistance.
  • no - the plant is eaten. Young plants may be eaten though.
  • favorite food - the plant is definitely eaten.
• Light Requirement heading:
  • sun - 6 or more hours of direct sun each day.
  • pt sh - up to 6 hours of direct sun each day.
  • sun to pt sh - must have some direct sun each day. Flowers better in more direct sun.
  • shade - no direct sunlight.
  • pt sh to shade - less than 6 hours of direct sun to no direct sunlight.
  • sun to shade - will grow in any amount of light.
• Soil Requirements heading:
  • moist - soil does not dry out quickly.
  • organic - soil has leaf mold or compost or other organic amendment.
  • well drained - soil does not remain soggy and rot the plant's roots.
  • infertile - opposite of organic - lacking soil amendments.

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Beech trees can be seen in many of the woods in Harford and Baltimore counties. They are very noticeable because of their smooth, light gray bark. In the winter, especially, the bark stands out, as well as the tan leaves that stay on the tree through late winter. The beech is a long lived, large-growing tree perhaps reaching 70 feet in height and spread, making a rounded or spreading tree in form. In the forest, though, its form in more upright to oval. The rate of growth is usually listed as slow (less than 12 inches per year), but in its youth the beech grows at a moderate rate (12 to 15 inches per year).
    There are two species of beech, Fagus grandifolia, American beech, and Fagus sylvatica, European beech. The American beech has the familiar serrated leaves and long, thin leaf buds. This beech prefers moist, acid soil and doesn't like wet, compacted soil. It does not grow well in the south. The European beech tends to have a more undulating and rounded leaf with not so much serration.
    The leaves are dark green on both species. I've noticed that the leaves are late to leaf out and usually don't appear until May. Both make beautiful specimens where there is room for them to grow.
    The American beech has no cultivars, but the European beech has many, especially dark red-leaved ones. Four are especially wonderful. The Rivers beech, Fagus sylvatica 'Riversii' has deep purple leaves that hold their color well into summer. It looks great as a specimen by itself, and in a loose grouping with thornless honeylocust, dogwood, and other light-green or blue leaf trees.
    Another splendid beech is the purple weeping beech, Fagus sylvatica 'Purpurea Pendula'. It is a wide-spreading tree as it does not make a central leader.
    An interesting cultivar is Purple Fountain weeping beech, Fagus sylvatica 'Purple Fountain'. This one does form a central leader with weeping branches. The leaves are a lighter purple than other purple beeches. This beech is much smaller growing and fits into most garden situations. It looks great as an accent plant with any number of deciduous and evergreen plants, especially with blue and light green leaves, and it can be planted in foundation plantings.
    The upright purple beech is called Fagus sylvatica 'Dawyck Purple' and grows to only 10 feet wide.
    The larger growing beeches should fit on a property an acre or more in size. They provide great dignity and nobility because of their form and size. Actually, they grow no larger than the oaks, spruces, and pines that dominate our landscapes. Purple Fountain and other smaller growing beeches can fit on any size property. Because of their longevity and beauty, any of the beeches, (there are others which I didn't have room to discuss here) would make a wonderful specimen tree for your garden or as a special birthday, wedding, or anniversary present.

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Hardy Camellias

Sometime in the mid 1970s, I visited the camellia collection at the US National Arboretum in Washington, DC. We fell in love with their large blossoms and their glossy evergreen foliage. Not too long after our visit, we purchased from the original Sweet Air Nursery a beautiful pink camellia with glossy, medium-sized leaves. I didn't record the name. Overall, the foliage survives most winters in but many years it doesn't flower because it really isn't hardy enough for this area. One year it was in such bad shape that we cut it to the ground to rejuvenate it which it did very quickly. Once it was established, this camellia has been a very low maintenance plant.
    In the late 1970s you may remember that Harford County had very severe winter weather and many of the less hardy plants died or were badly damaged and had to be destroyed. Plants like Lagerstroemia (crepe myrtle), Cedrus deodora (Himalayan Cedar), Ilex aquifolium (English holly), and camellias were affected. We went to see the camellia collection in the early 1980s. It was really heart-breaking to see the devastation caused by the severe winters. Most of the camellias had stems but no leaves. It wasn't a pretty site.
    As a result, Dr. William C. Ackerman, research geneticist of the US National Arboretum started a breeding program combining the only camellia species that survived at the collection Camellia oleifera (tea oil camellia) with the spring- and fall-flowering camellias. Dr Ackerman tested for cold hardiness thousands of seedlings from the crosses he made. His selections are cold hardy as well as have beautiful flowers.
    Dr Ackerman has already released many of the new hardy fall-flowering camellias from this program to the trade and they have been available at wholesalers and garden centers for several years now. Most of them have names such as 'Winter's Rose' or 'Winter's Hope' and the tag explains that they are winter-hardy in our area. You'll find some of these plants listed in the Roslyn Nursery catalog (see my newsletter archives for information on this nursery).
    The fall blooming camellias have white, pink, lavender, and red flowers. Their forms range from single flowers to semi-doubles similar to Camellia japonica. The earliest blooming is C. x 'Snow Flurry' which starts in late September and continues to early November. C. x 'Winter's Beauty' produces flowers last with blooms appearing in mid-December and finishes in January.
    With the spring-blooming camellias, the first ones to bloom are C. x 'Spring Cardinal' and C. x 'Fire `N Ice' in mid-February. Flowering ends in April with C. x 'Kuro Delight' and C. x 'Spring Frill'. Open flowers can be hit by very cold weather, but there are many buds waiting to open once the weather improves.
    I am really excited about these new camellia cultivars. They open up great possibilities for our gardens. As you can see, there is wide range of bloom times making it possible to have flowers in the late fall, winter, and through early spring. Their ultimate size is 5 to 7 feet. They can be used in foundation plantings, as hedges, specimens, in special winter gardens, and in part shade gardens.
    Camellia culture is simple: plant in slightly acid, moist, well drained soil amended with peat moss or compost. Since the camellias are understory shrubs, part shade is best. A north or east facing location would be great as long the plant gets some sun. As with azaleas and rhododendrons, this is one plant that doesn't mind being planted 1 inch or even 2 inches above the bed level. To establish the plants well, water once a week, as needed, for the first two years. Once established, water during dry periods. Use an acid-type balanced fertilizer in the spring. A slow release fertilizer would be great.
    If you are interested in a list of these camellias, email or call me and I will send it to you.
    Based on an article in the December 1, 2000 issue of the American Nurseryman magazine.

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Clematis "Polish Spirit" is a prolific summer-blooming vine for sunny locations. Its small purple flowers (about 4 inches wide) bloom on a vine that grows to about 12 feet high. It is less susceptible to clematis wilt than many of the larger-flowered clematis. Since clematis are thirsty growers, we water all of our clematis at least weekly if there hasn't been enough rain until they have finished blooming. Clematis also need to be fertilized on a regular basis up to the time they start blooming. Don't fertilize while blooming as it will shorten the blooming period.

This is how we are planting clematis now:

• cut the bottom off of the pot;
• dig a hole as wide as the pot or a little wider;
• dig a hole as deep as the pot plus three inches for burying plus another 12 inches for amended soil under the pot. The hole will be about 24 inches deep.
• amend the bottom twelve inches of soil with compost or peat moss and perlite for improved drainage and moisture retention.
• firm the bottom 12 inches of soil and rough up the bottom roots of the plant and place on top of this amended soil so that the top of the root ball is three inches deeper than the surrounding soil level.
• place three inches of amended soil on top of the root ball;
• add three inches of mulch on top of planting site.

As Polish Spirit is a short grower, we don't prune it.

Fothergilla gardenii or Dwarf Fothergilla is one of my favorite plants. It isn't flashy in flower with its small, creamy-white bottlebrush-like flowers in early spring. It isn't overly fragrant; some years it is more fragrant than others though. Sometimes as I pass close by fothergilla, I can smell its sweet, honey scent. It has very attractive leaves somewhat similar to the witchhazels (Hamamelis) to which they are related. It also has an attractive shape and is slow growing. It's a small shrub, slow to start growing; and the stems have a zig-zag look similar to the honeylocust (Gleditsia). The blue-green, leathery leaves are always attractive and never look eaten by insects. They don't get mildew, and they are gorgeous in the fall, turning shades of scarlet, orange, and yellow.

Fothergillas prefer moist, acid soil with organic matter worked into the soil at planting time. Full sun is best for flowering and fall leaf color but part shade will do, which is where mine grows. It grows well in clay soil that's been amended with peat moss.

As for uses in the landscape and garden; mine is growing as an accent among low-growing ground covers. It's largish leaves are a nice foil against the fine leaves of Phlox subulata (moss phlox) and Juniperus procumbens 'Nana' (Japanese garden juniper). I've placed fothergillas in foundation plantings and with groupings of rhododendrons and azaleas. It will also work as an accent plant in perennial beds and in native plantings.

There are quite a few cultivars, but the two most popular are:

F. g. 'Blue Mist' has more blue foliage than the species. Its leaves don't always turn brilliant colors in the fall.

F. g. 'Mt Airy' has blue-green foliage and consistently changes color in the fall. It seems to be a stronger grower than the species.

I've used both cultivars in landscapes I've designed and I prefer the species. In this instance, it seems that newer is not better as the species seems to be a better plant because it is slow growing and its leaves turn beautifully in the fall. I wouldn't want to be without Fothergilla gardenii in my garden.

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Indigofera kirilowii . . .

Six years ago I planted a false indigo I purchased from Plant Delights Nursery. I've ignored it for the past several years. Last year I removed Phlox ‘David' that was next to it because I wanted to plant a new Caryopteris (Blue Mist Shrub) in its place. Once the Phlox was removed the false indigo started to shine since it was no longer competing with the large mass next to it. Actually, when it is in bloom it is the centerpiece of that area.

Indigofera kirilowii is its botanical name. It is a small shrub growing to three feet by three feet and is easily pruned after it flowers. Its lovely pink flowers appear during June and July. My plant was blooming at the end of May. It has nice, bright-green, pea-like leaves as you can see from the picture. I have never really noticed it's fall color so I assume there is nothing special about it. In cold winters it could die back to the ground but will readily grow again from its roots. It flowers on new wood which is similar to the Buddleia.

I planted it in the only sunny spot in my back garden and it has done well with very little care. The catalog information notes that it needs moist, organic, and well drained soil. It is growing very well in clay soil and as I said before, it really doesn't get much care except a hair cut in early spring. It is watered when the other plants around it need water. Since it was next to a garden phlox it did receive water during drought periods as I did water the phlox then.

In my garden it is planted among yellow-leaved plants. That's Sedum 'Angelina' in front of it and a large-leaved Bergenia planted to its right. The plant comes from Korea and is hardy to USDA Zone 5. I have not seen any seedlings from it at all. I have read that since it readily puts out new shoots from its roots it can be used as a ground cover. It might be a great addition to sunny slopes for that reason.

When searching the internet to see who carries it, just a few mail order nurseries do. I think I have seen this plant recently at some of our local nurseries. If you need a plant for a sunny location, check to see if your local nursery carries it. If not, it's worth a search. Actually this plant purchased from Plant Delights Nursery were from Christopher Lloyd's garden and grows to only 18 inches tall and that's the height of my plant as well.

Syringa reticulata--Japanese Lilac--is a wonderfully fragrant small tree that blooms in mid-June. Its fragrance is not the same as the earlier lilacs but it is still nice. Chanticleer has planted a grove of the cultivar 'Ivory Silk' near the walk to the Asian shade garden. When it's not in bloom it has a horizontal look--not unlike our American dogwood, Cornus florida. This tree can be planted near walnut trees as has also been done at Chanticleer. This cultivar could be a substitute in sunny places for the dogwood. It's a small tree perhaps growing to 20 feet tall and wide. The flower color is white to creamy white.

Japanese lilacs are very adaptable as to soil and pH requirements and grow well in clay soil.

I enjoy using small shrubs in perennial gardens as they give a sense of permanence to the plantings. After flowering in the late spring to early summer, I can grow a low-growing summer-flowering clematis or annual vine over them to give the area another look for later in the summer. The spireas are especially nice to use because they are low maintenance plants with a big impact, especially those that have brightly colored leaves.

I prefer to use the smaller-growing ones which include the species japonica and the Bumald spireas (crosses made between japonica and albiflora, the white Japanese spirea). They can also be used in masses as tallish ground cover.

There are many cultivars of Japanese spireas and it is difficult to pick the ones to discuss but here is a short list of my favorites.

• S. japonica ‘Gold Mound' is a favorite of mine with fine gold leaves throughout the growing season and pink flowers in May and June. By late summer the gold color fades more toward green but still shows some gold. The foliage changes to orange red in the fall. It grows to about 2 to 3 feet tall and 3 to 4 feet wide.
• S. j. ‘Little Princess' has green leaves and rose flowers. It will grow to 2.5 feet tall and 3 to 4 feet wide.
• S. j. ‘Neon Flash' has rich red flowers and reddish new growth and grows to 3 feet tall and 3 to 4 feet wide.
• S. x bumalda ‘Goldflame' is a very popular cultivar with good reason. Its leaves are orange to bronze-red when they first emerge in the spring and put on a good show. Eventually then turn green in the summer and coppery in the fall. It's flowers are pink. Goldflame grows to about 2.5 feet tall and 4 feet wide.
• S. x b. ‘Limemound' has bright lemon yellow leaves in the spring turning to lime green in summer. Fall foliage is orange-red. It's flowers are pink too and grows to 2 feet high and 3 feet wide.
• On a recent visit to Chanticleer gardens I spotted a flowering shrub in the Asian Woods that looked like a spirea but it was blooming in the shade. I found a tag and it was Spiraea miyabei, a Japanese spirea. As you can see from the photo at right, it has beautiful bluish leaves, large flower heads, and I have learned that the leaves turn a nice red-orange in the fall. It grows to about 3 feet by 3 feet in a rounded form. Roslyn Nursery is selling it in its Spring 2002 catalog.

As I mentioned, spireas are low-maintenance plants. Michael Dirr's "Manual of Woody Landscape Plants" lists a variety of insects and diseases that affect spireas, but after growing some of the above listed ones for several years, I haven't seen any problems with them even when the spireas are grown in less-than-optimum conditions, including drought. Except for S. miyabei, they require sun to very light shade and average garden soil. What could be easier? Prune these spireas in early spring before new growth starts as they flower on new growth. After it flowers, cut back the plant for new bright leaf growth and new flowers later on.

Some garden writers consider spireas as overused in the garden. I don't see them enough when garden visiting. It's so much fun using spireas to come up with just the right color combinations with perennial plants. The larger geraniums, echinops, veronicas, campanula, and the later blooming perovskia would all work well with them. Spireas look good too with ground covers such as the Japanese Garden Junipers, Juniperus procumbens nana. If tall summer-blooming lilies are placed close to and behind the spireas, the spireas will cover the lower stems and shade the roots of lilies such as Lilium ‘Casa Blanca'.

With their small size and great foliage and flowers, why not use them as much as possible! I certainly do.

Stewartia - Exfoliating Bark

Why plant a tree that no one else has heard of? Many times a little known plant is perhaps new to the gardening world or may be difficult to propagate. Many of these little-known plants have qualities that make them very special. The Stewartia pseudocamillia has lovely white camellia-like single flowers in June and July and beautiful exfoliating bark all year-round. A real plus is that it doesn't have any disease or insect problems. The tree isn't too fast growing or too slow growing either, and the tree exhibits this beautiful exfoliating bark at an early age.>
    Many landscape designers try to work with a plants that are a little different from the usual and offer something of interest all through the year. Stewartia pseudocamellia and some of its related species provide four seasons of interest. Its white flowers are lovely when in bloom; during the rest of the growing season its foliage is refined and attractive; in the fall the tree colors well to a dark red color; and in the winter the bark is very interesting because it is smooth to the touch and exfoliates (peels off) into beautiful patterns.
    Japanese Stewartia is a small, ornamental tree growing to about 30 feet. The white flowers are about 2.5 inches wide with orange stamens, cup shaped, and similar to a single white camellia flower. Since the flowers open over a long period of time in mid¬summer, there is not a flashy flower show. The flowers do stand out from the nice dark green leaves though. The overall tree outline is softly pyramidal. Leaf color in the fall may turn yellow, red, or dark, reddishpurple. The tree should be planted where the bark can be easily viewed and enjoyed. The reddish-brown outer bark peels away in irregular patches to reveal a cream-colored bark underneath.
    Stewartias require sun with some shade during the hottest part of the day. I have my Stewartia planted in a lightly shaded area and it does very well. Stewartias require moist, well-drained, acid soil with high organic matter content so add peat moss and/or compost liberally to the planting hole.
    If you want to see a mature specimen, there is a Stewartia at Winterthur on the left side of the main drive just after you cross the bridge over Clenny Run (where the ducks often make you stop and wait for them to cross the road). There is also an Acer griseum (Paperbark Maple) and a heliotrope tree in the group. There is a variegated-leaf Stewartia in the White Garden at Ladew Topiary Gardens in Monkton, Maryland. It is at the far end of the White Garden area across from the Teahouse garden.
    There are other species of Stewartia. Stewartia ovata (Mountain Stewartia) is a tree native to North Carolina and Tennessee, but the bark does not exfoliate like S. pseudocamillia. Stewartia koreana (Korean Stewartia) has slightly larger flowers and exfoliating bark. The bark of Stewartia malacodendron (Silky Stewartia) does not exfoliate either. Stewartia monadelpha (Tall Stewartia) is another native tree and has a rich cinnamon-brown bark. There is a lovely specimen of this tree at Brookside Gardens in their shade area near the viburnums. Not all of these trees are widely available.
    Plant Stewartia near a terrace or low deck or along a path or walk that is used often, such as the path to the front door. Trees with exfoliating bark are interesting to look at in the winter. The form of the tree can be studied more easily without the leaves, and the bark, too, can be studied and enjoyed. Exfoliating bark comes off the tree in pieces. Depending on the genus, the pieces can be large or small. On the Stewartia, the exfoliating pieces are not so large as to be a nuisance. Plants with interesting bark and/or shape should be planted so they can be seen from a window used often in the winter. Perhaps the tree can be used to hold a bird feeder in the winter so you can enjoy the antics of the birds as well as view the bark of the tree. Early spring bulbs such as crocus and fragrant daffodils can be planted around the tree to provide additional interest in the spring. Perhaps a groundcover of green liriope can be planted as well to protect the bark from the lawn mower and string trimmer and to provide interest in the late summer with lavender flowers and in the early fall with their dark berries. As the tree matures, perhaps a small sitting terrace can be installed on its shady side and some additional flowers and a birdbath added to provide a lovely scene that can be viewed from the house and enjoyed any time of the year.

. . . Viburnum plicatum var. tomentosum 'Summer Snowflake' is going to be a popular shrub because of its attractive white flowers blooming off and on throughout the summer. Many years ago I went to a lecture at Ladew Topiary Gardens that the late Dr. J. C. Raulston of the North Carolina State University was giving. One of the introductions he talked about was 'Summer Snowflake'. I asked him after the lecture where I could get this wonderful plant. He said his program of disseminating plants didn't apply to home owners (I wasn't a designer at that time). Some time later, though, I received a box of three beautiful, small Summer Snowflakes from Dr Raulston. I planted them in a shady area where they are doing well . But the area doesn't show them at their best. I finally have another one which I've planted in a better place that shows off the lovely white flowers throughout the summer.

This cultivar is much narrower than it parent, the Doublefile Viburnum. It grows to about eight feet tall and 5 feet wide, versus 12 feet wide and tall for its parent. It's controlled size makes it great to use as a specimen, a hedge, or in a grouping of 3 to 5 plants. These viburnums, whether the standard Doublefile or the 'Summer Snowflake' make a nice substitute for our dogwood in sunny or part shady spots. Wayside Gardens and other mail-order catalogs sell this plant. I haven't seen it too frequently in retail nurseries. If your favorite nursery doesn't have it, ask them to get a few. I'm sure once gardeners see the lovely summer flowers, it will sell itself.

Because of its large leaves, if it is planted in a dry spot, such as on the crest of a hill, it will need careful monitoring during its establishment period so it doesn't wilt.

The doublefile viburnums need moist, well drained soil and grow in sun to part shade. I have been growing the viburnums for many years now and I have found that once established they are drought resistant plants.

For more information on the many viburnums that grow well in our area click on Viburnums -- Shrubs for Three-Season Interest

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