Specifics for our Colder Climates
In colder climates where temperatures drop below 0°F (-20°C) foundation planting and mulch are required to ensure a long life. High light and long days can be ideal growing conditions for clematis if a little care is taken when planting. By following our planting instructions, most varieties will survive and flourish.
Clematis set their buds when their stems reach the proper degree of hardness, so clematis which take a full season to ripen in our temperate regions, will ripen and bloom in the same season in our high light, high heat regions.
If a group B clematis has its top growth frozen to ground level, when planted properly (planting instructions followed explicitly), new growth will come from buried dormant buds, and you will enjoy your flowers in mid summer rather than early summer. Because of the hot dry climate of these regions it is imperative that clematis have shelter from a baking hot sun. If planting on a sunny south or west wall clematis need to be protected from the reflective heat of the sun. Under these conditions the old adage of “their heads in the sun and their feet in the shade” must be adhered to at all times. An excellent method of accomplishing this is to plant behind a low growing shrub that will give shade to the first 3′ (1m) of the plant.
Double flowering varieties are usually not recommended in colder zones. They grow fine; however, if the tops freeze back and the previous season’s growth is lost, single flowers only will be produced. If any double flowers do develop they will occur late in the season rather than early.
Specifics for more Temperate Zones
In our temperate regions where temperatures never drop below 0°F (-20°C) clematis plantings are limited only by imagination. Picture clematis cascading over a fence; enjoy a vine covered cottage; delight in it rambling through your trees. One of my favorites is a climbing rose with a summer blooming variety roaming through it.
Clematis are not a heavy strangling vine. They grow through their host doing very little damage. If planting against a wall, your trellis should be constructed in such a way that it can be let down in one piece at house painting time. Most varieties perform well in full or filtered sun. Although clematis prefer four or more hours of good light each day, they will grow in most locations, including a bright north wall. The pastel colored hybrids have more intense blooms if grown in one of your shadier locations.
Many varieties of clematis are ideally suited to container growing. Special care must be given to choosing the right container, the right support, the right soil and of course the variety – just right for that special spot. The minimum size of container is 18″ wide by 18″ high by 18″ deep (45cm x 45cm x 45cm). In picking a container, metal or any material that conducts heat should be avoided. A potting soil with a high content of coarse peat moss will help retain moisture but also provide sufficient drainage. Proper support is very important. If you are going to grow your clematis against a wall, a trellis of some sort is required. In lieu of a trellis sweet pea netting stapled to a fence or wall serves as an inexpensive and effective support. If you wish to have your container free standing, a tripod of bamboo or cedar stakes works very well.
A tripod of strong canes makes a good free standing support. Many different trellises work equally well.
If your container is large enough annuals or a ground cover can be planted on the surface. Feed and water often to encourage blooms all summer.
The root ball should be in the center of the container.
Use a good potting soil.
Be sure to allow good drainage.
Clematis need something to climb on. Sweet pea netting or plastic mesh work well. Carefully but securely attach vine to cane. Back fill with good quality top soil mixed with a handful of bone meal (if your soil has a high clay content add peat moss). The top of the root ball should be at least 6″ (15cm) below ground level. A layer of good top soil (if soil has a high clay content add peat moss). Place 6″ (15cm.) of well rotted manure mixed with good top soil or compost. Where practical it is a good idea to plant a small shrub to shade the roots of your clematis.
It should be pointed out that the clematis you plant today needs to be happy with the effort you put into its planting site for the next several decades. There are clematis over eighty years old still blooming marvelously.
Clematis need a cool, moist, deep root run, plenty of water and regular, balanced feeding. A little special preparation will ensure the proper environment. Dig a hole eighteen inches deep by eighteen inches wide [45cm x 45cm x 45cm]. Cover the bottom with a good rich compost or well rotted manure. A hand full of bone meal mixed with your soil is always a good idea. Add enough topsoil to cover the compost; now you are ready to plant. Place your well watered clematis in the hole so that about six inches [15cm] of stem is below the soil line. The stem of your clematis needs to be ripe before you bury it. If you are concerned about this, leave the final filling of the hole until later in the season. The stem of the newly planted clematis needs to be securely but carefully attached to a support so that damage to the stem does not occur. Planting a small shrub in front will insure a cool root run for the clematis.
If possible plant outside the drip line of the host tree. Clematis need something to climb on sweet pea netting or plastic mesh work well. Carefully but securely attach vine to cane. Where practical it is a good idea to plant a small shrub to shade the roots of your clematis. Back fill with good quality top soil mixed with a handful of bone meal (if your soil has a high clay content add peat moss). The top of the root ball should be at least 6″ (15cm.) below ground level. A layer of good top soil (if soil has a high clay content add peat moss). Place 6″ (15cm.) of well rotted manure mixed with good top soil or compost.
Whenever the ground is workable clematis can be planted. Clematis react to the seasons much like bulbs. In the summer and fall there is vigorous root growth storing energy for top growth and flowers the following spring. Come spring, clematis will produce two or three feet of top growth before you notice any root activity. For this reason, in mild regions fall planting is ideal. If one chooses to plant in spring or summer, it is useful to periodically pinch out the growing tips.
If you choose to plant in the fall, you will want to prune the following spring, no matter which pruning group your clematis belongs to. Although this will inhibit flowering for the first year, it will help promote root development and produce a bushier plant.
If planting is done in the heat of the summer, it is essential that sufficient water is provided to keep roots moist and cool.
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