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, we share all you need to know about growing ‘Jackmanii’ Clematis, including maintenance and care.
I. Appearance and Characteristics
Clematis ‘Jackmanii is a Clematis cultivar which, when it was introduced in 1862, was the first of the modern large-flowered hybrid clematises of gardens. It is a climber with large violet-purple blooms, still among the most familiar climbers seen in gardens. It was produced from crosses made by the prominent nurseryman George Jackman (1837–1887), of Jackman & Sons, Woking, Surrey.
C. ‘Jackmanii’ arose from crosses made in 1858 between Clematis lanuginosa, the red form of C. viticella, and an earlier garden hybrid, Clematis × hendersonii, which the new hybrid eclipsed. The spectacular success of ‘Jackmanii’ encouraged Jackman & Sons to introduce a series of clematis hybrids, although none of these ousted ‘Jackmanii’ from favour. Jackman also produced a monograph, The Clematis as a Garden Flower (with T. Moore, 1872), which he dedicated to H.S.H. Princess Mary, Duchess of Teck, as the clematis was one of her favourite flowers.
Few of Jackman’s early hybrids survive today, in part because they were grafted, often on ‘Jackmanii’, but the dependable, floriferous and hardy ‘Jackmanii’ itself remains one of the most popular clematises of North American farmyard gardens in the East and the Midwest, where it is hardy to USDA Zone 4a; it is seen grown on trellis, fence, arbor, porch pillar, or lamppost, wherever the soil retains some moisture and the roots are shaded, even if only by a large flat rock. The plant flowers on the year’s new growth, so pruning is best done in early spring, before the plant leafs out. Cut to the ground the plant can reach 3 metres (10 ft) during the season; a column of bloom can be achieved by pruning out stems at varying heights, some as low as four buds, others above head height.
II. How to Grow and Care
Sunlight
Treat this flowering vine as a perennial vine for sun in the north. But it can take a bit more shade than can many other types of clematis; in the south, it is a good idea to give it partial shade.
Temperature and Humidity
While Jackman’s clematis likes warm weather, it does not do well in excessive summer heat, especially if it is planted in a location where the root zone gets hot. It does not have any particular humidity preferences.
Watering
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.
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.
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 with cuttings made from new, soft green growth.
- Take a cutting below a leaf node. Your cutting only needs one leaf stem, so trim off any extras.
- Dip the cut ends in rooting hormone. Fill a 4-inch pot with potting mix. Lay the cuttings on top horizontally. Lightly cover with potting mix and moisten the top with water.
- Place the pot in a clear plastic bag and keep it in bright but not direct light, Keep the soil evenly moist but not soggy. In about four weeks, the cutting should have rooted. You’ll see new growth and the cutting won’t wiggle when you gently tug on it.
- Transplant each rooted cutting in its own pot. Leave it in the pot for another growing season and harden it off before transplanting it outdoors.
How to Grow from Seed
This variety is a hybrid and seeds collected from it won’t produce plants that are true to type. Therefore growing it from seed is not recommended.
Mulching
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.
Pests and Diseases
Common Pests and Plant Diseases
Slugs like to eat clematis almost as much as they do hostas. If you use stones to shade the base of the plant, lift them often to check for slugs napping beneath. Dispatch any slugs that you do find. Pest damage can also come from earwigs and spider mites.
Clematis wilt, a fungal disease that attacks the base stems of the plant, can be fatal to clematis. Its symptoms are a sudden progressive shriveling of the entire plant, usually in early summer. Black spots on the leaves may be evident. There is no cure for clematis wilt, but you may be able to prevent it by keeping the soil evenly moist, making sure the soil is neutral or slightly alkaline, and watering at the base of the plant rather than on the leaves.
If clematis wilt appears, remove all damaged portions of the vine. If the root system is strong, the plant may recover by the next season.
Common Problems
The roots of clematis do not like heat so it is critical to shelter clematis roots from the blazing sun. You need to take measures to keep the roots cool. The practice of deep planting helps keep the roots cool. Another way to keep your vine’s roots cool is to spread about 2 inches of mulch over the root zone. Other gardeners shade the base of the vine with ground covers, which is not ideal because they can interfere with the root system of the clematis. Still others place flagstones or other objects at the base of the clematis to cast shade. However, the latter practice can provide an open invitation to slugs.
III. Uses and Benefits
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.
Find Where to Buy the Best Jackman’s Clematis (Clematis x jackmanii)
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