How to Plant, Grow and Care for Clematis ‘Jackmanii’
Are you looking for a unique flowering vine to add to your garden this season? 'Jackmanii' Clematis might be just the right plant to liven up your gardening space! In this article, gardening expert Liessa Bowen shares all you need to know about growing 'Jackmanii' Clematis, including maintenance and care.
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!
|common name Jackman’s Clematis, Clematis x Jackmanii, Large-Flowered Clematis|
|botanical name Clematis ‘Jackmanii’|
|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|
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.
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.’
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The most common issue you may have is root rot, caused by plants sitting in wet soil for prolonged periods of time. You may notice your entire plant is drooping severely.
Check the soil around the plant. If it’s saturated, your plant may be starting to rot, and you will need to promptly move it to a drier spot. Root rot is easily preventable by using well-drained soil and putting your plant in a location that does not retain water.
Leaf spot is caused by fungal infections on the leaves. Leaves develop large dark spots and will eventually wither and die. If you notice this happening to your plant, remove the infected leaves as soon as you notice them. For more extensive infections, apply a fungicide to any infected areas.
To prevent plants from developing leaf spot, make sure there is good air circulation around your plants. Try also to water them at the base, so water doesn’t sit on the leaves unnecessarily. Treat any diseased plants promptly to prevent spread to nearby healthy plants.
Clematis wilt is also caused by a fungal infection. As with leaf spot, leaves will develop dark spots and will eventually turn black or brown, wither, and die. Diseased spots spread from the leaves to the stems and the entire plant will eventually wilt, turn brown and die.
Prune infected leaves and stems as soon as you notice any sign of infection. This will help keep it from further spreading. Apply a fungicide and try to give the plant some distance from other nearby vegetation to improve air circulation.
Powdery mildew is a relatively common infection caused by a fungal infection. The first thing you will probably notice is a white to grayish-white spotting on the leaves. It may initially appear as a few isolated spots but quickly spreads until the entire leaf is discolored. Leaves will eventually wither and die.
Remove severely infected leaves and try to provide ample air circulation for your plants to prevent future infections. There are products available to specifically treat powdery mildew, such as copper sulfate or sulfur. Be sure to carefully follow directions for any products you use on your plants.
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.
If you have ever wanted to try growing a Clematis in your garden, try Clematis ‘Jackmanii.’ A Clematis will look stunning almost anywhere you plant it, so be sure to put is somewhere it will be fully appreciated. Give it a sunny spot with moist, well-drained soil.
Provide it with a trellis or other climbing support and keep an eye on its general well-being. With a little care and attention, your Clematis will reward you with reliable summer blooms for many years in the future.