Long a favorite with landscape architects, the showy clematis blooms afford a striking accent to the summer garden, mainly when used as a background for a wide variety of lilies.
Versatile, generally pest-free, and when once established, capable of surviving severe winters, clematis may be called genuinely spectacular. They are equally attracted to roses.
The secret of success with clematis lies in a proper selection of varieties and adherence to planting and cultural needs. Not all types will grow equally well in a given area.
Differences in soil composition, extremes in temperatures, improper fertilizers or watering, failure to mulch for the colder climates, and planting too deep—constitute most reasons for failures. A request to the nearest agricultural center will bring a variety list best suited to one’s area.
Clematis: Feet In Shade, Heads In Sun
In general, like lilies, clematis should have their feet in the shade and their heads in the sun. They are best suited for growing on trellises, fences, lamp posts, old tree stumps, stone walls, brick or frame walls of houses or garages, outdoor fireplaces, porch arbors—any place where they can be trained to climb on chicken wire or other supports.
Prepare The Soil Bed
Adequate preparation of the soil bed where they live for many years is a prerequisite. Select a site where plants receive full sun for at least six hours daily.
Dig a hole 2’ feet wide and 2’ feet deep. Ensure drainage by pouring a gallon or two of water into the excavation. If the water drains away within an hour, all is well.
The soil should be well-drained loam fortified with humus such as leaf mold or peat moss, a cupful of balanced commercial fertilizer to which a generous amount of sand is added, and an application of ground limestone (one quart) with about three cupfuls of bone meal. Mix well, water, and allow the soil to settle for a few days.
The bed can be prepared for spring planting as soon as the soil is workable. Spread out the roots in the planting hole and cover the crown with no more than I 1/2″ to 2” inches of soil. Firm the vine in place and water. If any stems are broken, they should be removed.
Use A Starter String
Use a starter string or petite, slender stake for the shoots to cling to until enough growth has been made for the vine to reach its permanent support. Prepare a mulch of three pieces of peat moss and one part of dried commercial manure.
This should be placed over the bed to a depth of 4” to 6” inches and well around it to keep the roots cool and moist in winter to help keep out frost. Manure is not recommended in the bedding soil, for it has encouraged root-rot nematodes.
As the vine becomes established, examine it periodically for stem kinking, which, if not straightened out, will shut off the food supply.
Provide Shade For Lematis Roots
Shade may be provided by planting ground covers near the main stems. These can be myrtle, pachysandra, ivy, or the like. When cold weather approaches, the vines will benefit from a generous hilling of soil and a covering of straw or leaves, especially over newly planted ones.
Pruning of clematis is a big subject. Remember that hybrids (the significant, showy kinds) are not as rampant growing as the species; therefore, little pruning is necessary and only on well-established vines.
Removal of dead wood after buds are visible usually suffices unless growth has produced a mass of tangled and bunched stems that crowd out flowers.
Then, too, certain varieties will have a top increase in winter killed, which cut the vines back to live growth in spring, the same way hybrid tea roses are pruned.
If rabbits or mice are a problem, a wire screen around the stems keeps them from nibbling the branches.
Pests and Diseases
Clematis has, in the main, few troublesome diseases. One of these is root nematodes. These are tiny worms practically invisible to the naked eye.
Another name for them is eelworms. Where or how they infest our gardens is subject pathologists have long studied. They may be introduced in new soil or carried in by heavy rains or winds from nearby infected plants.
Manure in the bedding soil has been known to harbor and encourage the growth of these pests. Their presence is revealed by a gradual wilting of the plants, especially after prolonged rains, or so it seems.
Applying a soil fumigant placed deep enough but without disturbing the roots will generally eradicate them.
Nematodes do not present too significant a problem in regions of cold winters because most kinds (and there are many) are winter-killed. It is mainly in the warm climates of Southern states that they become a significant problem.
Troublesome Aphids
Aphids can be troublesome. These tiny living hypodermic needles may infest clematis to a considerable degree. They suck the sap in leaves, causing them to be dry and brown. Periodic sprays with nicotine sulfate will eradicate them.
Certain varieties are susceptible to a form of rust similar to that on roses. Usually prevalent in hot, muggy periods of high humidity, rust causes the foliage to become underscored with brown lesions, which, if unchecked, will cause the leaves to curl and dry up. The best remedy is periodic sprayings or dustings with verbal or Fermate.
Be careful not to use over 20% percent sulfur preparations, especially when temperatures are above 75° degrees Fahrenheit. Too much sulfur will burn the foliage and leave an unsightly residue.
In general, clematis is remarkably free of disease, especially in cooler climates. Certain varieties seem more readily inclined to develop good growth than others. Be encouraged if a whole season is required for the roots to become established.
Keep the plant moist but not soggy; add a little lime from time to time. Your patience will be rewarded with a profusion of bloom, and the plant will produce for many years.
Clematis Bloom Size
Clematis blooms range in size from the panicles of the fragrant white Paniculata (sweet autumn clematis) with thousands of tiny flowers to the giant petals of Clematis Henryi, often measuring 8” inches across. Between are wide varieties of star-shaped, varicolored ones 3” to 5” inches across.
The steel-blue urn-shaped C. crispa or curly clematis, as it is often called, and the reddish-rose of the curious urn-shaped C. texensis, a variety also known as C. coccinea, of the South, are indeed oddities worth including in any garden, for they are herbaceous in cooler regions and send up new growth each year.
With proper selection, one can choose vines varying in height from 6’ to 20’ feet.
What To Do With Clematis Seeds?
Many gardeners need help figuring out what to do with the clusters of feathery achenes (seeds) which follow the flowers. Since they are decidedly ornamental, I allow them to remain on the vine until ripe. A few pods are left to drop their seeds, and the rest are removed.
The seeds are immediately worked into the topsoil before birds find them, and I often have a few new plants the following season for transplanting elsewhere or to give away.
Not many gardeners know it, but clematis may be grown indoors in a sunny window all winter long. It will blossom with the same flowers outdoors in a relatively short six to eight weeks. Just pot it in a planter box or a 4” inch pot in rich light soil.
Use moderately loose planting. Insert a trellis or stake when planted; keep moist but not soggy. Average house temperature and a sunny window are all that is needed. The plants can be transplanted outdoors through flowering.
Blooming Times For Old-Time Clematis
They are relatively easy to grow.
Blooming Times – June to September
- Fairy Queen – White
- Fairy Queen – White
- * Henryi – White
- Lanuginosa Candida – White
- Marie Boiuolot – White
- Miss Bateman – White
- Mme. LeCoultro – White
- * Jackmani – Violet to purple
- Jackmani superba – Violet to purple
- Lord Neville – Violet to purple
- * The President – Violet to purple
- Lady Betty Balfour – Violet to purple
- Crimson Star – Red
- Ernest Markham – Red
- Henry Chapin – Red
- Jackmani rubra – Red
- * Mme. Edouard Andre – Red
- Ville De Lyon – Red
- Barbara Jackman – Two-tones
- * Nelly Moser – Two-tones
- W. E. Gladstone – Lavender
- Wm. Kennett – Lavender
- Ascotiensis – Blue to purple
- Elsa Spath – Blue to purple
- Lawsoniana – Blue to purple
- Mrs. Cholmondeley – Blue to purple
- Mrs. Robert Bryden – Blue to purple
- Mrs. P. B. Truax – Blue to purple
- Princess of Wales – Blue to purple
- * Ramona – Blue to purple
- King Edward VII – Pink
- Mrs. Spencer Castle – Pink
Blooming Times – June to July
- Duchess of Edinburgh – White
- Belle of Woking – Blue to purple
Blooming Times – July to September
- Huldine – White
- Texensis – Red
- Crispa – Blue to purple
- * Comtesse Da Bouchard – Pink
- Mme. Baron Veillard – Pink
Blooming Times – May to June
- Montana alba – White
- Montana superba – White
- Montana rubens – Red
- Montana undulata – Pink
- Spooneri Var. rosea – Pink
Blooming Times – September
- Paniculate – White
44659 by Stanley H. Woleben