How to Plant, Grow and Care for Clematis ‘Jackmanii’

Clematis is a genus of plants encompassing over 250 species. It is a member of the Buttercup Family (Ranunculaceae). There is tremendous diversity within the Clematis genus, including both deciduous and evergreen vines, annual and perennial forms, and many beautiful varieties of flowers. Most Clematis, however, are perennial vines, and all have showy flowers.

One of the most popular Clematis varieties is Clematis ‘Jackmanii.’ While many Clematis hybrids may be difficult to find, ‘Jackmanii’ is more readily available.

Hardy and relatively low maintenance, it puts out a stunning annual display of large vining purple flowers each summer. Flowers are long-lasting and very showy. It’s no wonder ‘Jackmanii’ is so well-loved!

Clematis ‘Jackmanii’ Overview

	common name Jackman’s Clematis, Clematis x Jackmanii, Large-Flowered Clematis
	botanical name Clematis ‘Jackmanii’
	genus Clematis
	plant type Deciduous perennial vine
	bloom colors Purple
	sun requirements Full sun to part shade
	water needs Moderate
	height 7-10 Feet
	hardiness zones 4-8
	soil needs Well-drained
	where to plant Pergolas, Trellises, Arbors, Walls, Fences
	pet toxic Dogs, Cats, Horses
	propagation Cuttings

The Clematis genus was first published in the mid 1700s by Carl Linnaeus. Most of the popular Clematis today are of Japanese and Chinese origins, although there are also species of Clematis native to Europe and the Americas.

Clematis ‘Jackmanii’ is a hybrid cultivar derived by crossing C. lanuginosa with C. viticella. Clematis ‘Jackmanii’ was first introduced in England in the mid 1800s and has since climbed in popularity.

Growing Guide

Clematis are wonderful plants for the home gardener. If you have an available garden spot with some good sun and in need of a reliable show-stopping blooming vine, consider growing a Clematis. The guidelines described in this article will be widely applicable to many Clematis varieties, not just ‘Jackmanii.’

Choosing a Plant

If you have the opportunity to choose between several Clematis plants, you will, of course, want to choose a healthy one. How do you determine the healthiest plant? What should you look for before you buy?

Healthy Leaves. Choose a plant with bright green leaves and avoid plants with leaves that look yellowed or brown. The leaves and stems should appear fresh, firm, and vibrant. Avoid plants that are drooping, wilted, or soft. Choose plants with leaves that are solid green.

Fresh Flowers. If you are looking at plants already in bloom, choose one that still has many unopened flower buds. This way, you can enjoy your Clematis flowers for as long as possible.

Pot and Soil. Take a look at the pot. Is it cracked or damaged? Also, have a look at the bottom of the pot and make sure it has good drainage holes. Check the soil in the pot. Make sure the soil looks fresh and healthy. Avoid buying a plant where the soil looks green or slimy.

When to Plant

You just brought home a new Clematis in a pot. Can you just pop it right in the ground? It’s important to consider the time of year and weather conditions when planting your Clematis. Ideally, do your planting in the early spring or late fall, a time when the weather is reliably cool, and the sun isn’t as intense as mid-summer.

If you bought your plant in mid-summer, you can keep it in its original pot or transplant it into a slightly larger pot. You can wait until fall to plant it in the garden.

While maintaining your potted plant, check the soil moisture every day as potted plants tend to dry out very quickly. Keep it in a slightly protected place with good sun exposure, but it doesn’t need to be in full sun while you’re waiting to plant it.

If you really want to get your plant in the ground in mid-summer, try to choose a day that’s overcast and rainy. Follow the suggestions below and give it a little extra water and shade to help prevent transplanting shock. Many plants, Clematis included, don’t like to be planted in intense mid-day, mid-summer sun, and heat.

Where to Plant

Carefully consider where you want to plant your Clematis vine. The good news is that you have several options! Choose the one that’s right for you, your growing conditions, and your home gardening needs.

Planting in a Container

When you first bring your Clematis home, it will most likely be in a plastic nursery pot. It’s a good idea to transplant it into a place with more space for it to grow.

You can put it into a larger pot for a temporary home, but ideally, move it into a more permanent location as soon as it’s convenient and conditions are ideal.

Planting in a Planter

Some of the smaller varieties of Clematis are suitable for container gardening, but Clematis ‘Jackmanii’ would do best in a sunny space in the garden.

If you decide to use a planter, just be sure to use a large one, and place it in an area where your Clematis can climb. This vine can grow at least 10 feet tall and needs to be supported.

In the Garden

A sunny place in the yard or garden is the ideal location to plant your ‘Jackmanii.’ ‘Jackmanii’ is a vigorous climber and needs space to grow, climb, and sprawl. It would do well to be planted near a sturdy support, such as a trellis, arbor, fence, or wall.

Clematis like to be in a sunny spot but prefer their roots to stay cool and shady. You can therefore plant ‘Jackmanii’ in a location with some low-growing cover plants that will help protect its sensitive roots from harsh sunlight.

Select a Sunny Location

Clematis ‘Jackmanii’ needs full sun to part shade. It will bloom best in a location that gets at least 6 hours of bright sunlight each day.

You can plant it somewhere with afternoon shade, as long as it gets its minimum sunlight. Clematis won’t die when grown in more shade, but they also won’t grow well and may not have enough energy to bloom.

Grow in Good Soil

Use soil that is rich and well-drained. It’s very important that soil can be kept moist but not wet. Avoid planting Clematis in heavy clay soils or nutrient-poor sandy soils.

The soil should have plenty of organic matter and can include some organic compost as well. Soil pH should be neutral to slightly alkaline.

How to Plant

Prepare your planting location in advance. Dig a hole larger than you think you will need. Add some good-quality garden soil to the hole, and make sure the plant won’t be in a location that will hold water or be continually saturated.

Carefully remove your Clematis from its pot. Handle the plant gently because the vines, leaves, and flowers can easily be damaged and break off. Carefully set the roots into the new hole so the crown of the plant is slightly lower than it was in the pot. Cover the roots with fresh soil and pat it down gently to secure the plant in it’s new location.

Your ‘Jackmanii’ will need good support. If you are adding a trellis for the plant to grow on, you can put that in place now. If you want to train your plant to its support, use a few flexible ties to secure the plant to the trellis.

Alternately, you can very gently pull some vine strands through the trellis a few times until they are secure and don’t fall down. As the plant sends out new growth, it will continue growing on that support.

Give your plant a thorough watering immediately after planting to help it get settled in and reduce shock. Mulch around the plant with a generous layer of mulch to help keep the soil moist. This will also help keep the roots a little cooler during the summer months. For mulch, you can use shredded wood mulch, bark mulch, or hay.

Care and Maintenance

When it comes to proper care and maintenance, there are a number of factors you’ll want to consider. You need to ensure you are providing the right amount of water, sunlight, and fertilizer. You’ll also need to make sure you have planted them in the right location and provide the right climate.

Water

Clematis like to be kept moist but not wet. Check on your ‘Jackmanii’ regularly to see if it needs watering. At times when there is ample rain, it will probably be fine. But during times of dry weather, especially accompanied by hot temperatures, you may need to do a bit of extra watering.

Water the soil around your Clematis. Make sure you give it enough water so that the water penetrates the surface of the soil and reaches the roots. Clematis plants tend to form a dense mass of shallow roots around the plant, with a few deeper taproots.

Don’t let the roots stay very dry for too long, or the plant will start to wilt. Also, be careful not to let the plant sit in a soggy puddle. Clematis are very intolerant of constantly wet soil, which can easily lead to root and crown rot and a dead plant.

Mulch

It’s a good idea to spread some mulch around your Clematis plants. Mulch serves a couple of useful purposes. It can help protect roots from the heating and drying effects of the sun.

It can also help preserve soil moisture and prevent the roots from drying out quickly. Mulch in the winter is good for protecting the roots from extreme cold.

Climate

Many Clematis, including ‘Jackmanii’ are hardy in USDA Climate Zones 4-8. If you are in a location that experiences extreme weather, you may need to give your plant a little extra protection from time to time.

Give it extra water during periods of drought. Check its support structure during periods of high winds. Give it a bit of extra mulch to protect it from harsh winters.

Fertilizing

Your ‘Jackmanii’ will give its best growth and flowering with some regular fertilizer applications. Clematis is a heavy feeder and needs the extra nutrients to produce all those showy flowers.

Fertilize approximately once per month during the growing season. Hold off on fertilizer when the plant is blooming, otherwise, it may attempt to grow more vine at the expense of producing additional flowers.

You can use a general-purpose organic fertilizer. Choose one formulated for outdoor flowers and be sure to follow the directions for mixing and application. You won’t need to add any fertilizer during winter months.

Pruning

Clematis ‘Jackmanii’ belongs to Clematis pruning group 3. These are plants that produce flower buds and blooms only on new (current year’s) wood. Prune them in late winter or early spring before the plant has started to grow for the season.

Give them a fairly hard pruning, cutting back to approximately 12 inches above the ground level, just above a healthy leaf bud. The plant will then vigorously grow in spring and early summer and will produce new flower buds on this new growth.

Transplanting

If you have a Clematis planted and established in the ground and discover that it needs to be moved, you will need to do some careful transplanting.

Clematis do not enjoy being transplanted, and sometimes they don’t survive the ordeal. The best time to attempt transplanting clematis is in early spring before the plant has started to grow for the year.

Choose a cool and overcast day if possible. Prepare your new location in advance by digging a hole and adding some good soil. Carefully remove the plant from its current location by digging out as much of the root mass as possible, trying to keep the roots intact.

Keep the roots wet during the transfer process. Immediately place the plant in the new hole, cover it with fresh soil, and give it a heavy watering. Keep it well watered for the first few weeks and protect it from extreme sunlight until it gets established and looks perky again.

Propagation

Clematis can be propagated by softwood cuttings. Take your cuttings from fresh green growth in late spring to early summer when the plant is actively growing. Take several cuttings, as they probably won’t all survive.

Cut a few lengths of the vine into individual sections with a healthy set of leaves on top and a few inches of stem underneath. Dip each stem section in some rooting hormone for the best results. Plant these sections in moist potting soil and keep them both humid and moist.

Put your cuttings in a warm spot with some diffuse sunlight and give them about 4-5 weeks to develop roots. Cuttings that have rooted should grow into new Clematis vines. Those that have not developed any roots or that have turned dark and mushy should be discarded.

Transplant the successful cuttings into larger individual pots with good drainage and good quality potting soil. Allow these to grow in a sunny location for several months to a year before transplanting into the garden.

Pests and Diseases

Clematis are generally hardy and don’t frequently have problems with pests and diseases. Deer and rabbits don’t seem to bother them, and they rarely have problems with insect pests. Occasionally, however, something is clearly bothering your plant. Some of the more common pests and diseases are listed here.

Landscaping Uses

Clematis ‘Jackmanii’ and other climbing varieties of Clematis have a unique place in the home landscape. Because of their climbing and vining nature, they can be used to give vertical height to the flower garden. Provide them with a trellis, wall, fence, or arbor, and they will cover it with greenery in the spring and beautiful blooms in the summer.

These plants grow well on their own or with some shorter plants around their base. The shorter plants offer a bit of shade and protection to the Clematis’ sensitive roots and also complement the taller growth of the Clematis vine.

Try pairing your Clematis with a few other low-growing perennial flowers or small ornamental grasses that will shade the roots and provide complimentary shapes and colors around the base of the vine.

If you have a sunny space for a beautiful climbing vine, ‘Jackmanii’ is a good choice. The large, showy, vining purple flowers of ‘Jackmanii’ provide a memorable mid-summer display. Be sure to plant your Clematis in a location where you can see if frequently and enjoy its blooms.