Clematis Rouge Cardinal

Clematis ‘Rouge Cardinal’ – care and pruning

Categories: 3 pruning group, large-flowered, red clematis varieties, winter-hardy

The clematis variety “Rouge Cardinal” was obtained by A. Girole as a result of crossing clematis “Ville de Lyon” and “Purple Mat”. in 1968. This is one of the most popular clematis varieties in Russia (and before the appearance of “Taiga” it was the most popular) and one of the first varieties that a flower grower acquires consciously. Sometimes it is also called “Red Cardinal”, which is not quite correct.


Table of Contents


Pruning group 3 (strong pruning)
Pruning period October
Height 200…300 cm
Flower diameter 10…15 cm
Flowering June through August
USDA 4-9


Rouge Cardinal grows up to 4 meters tall, but this is far from immediate. In my first year, the annual barely reached a meter in length and all of it froze over the winter. The next year the clematis grew from a bud in the ground and grew about 50 centimeters. This shoot has already been saved, and now, in mid-July, it is a meter and a half. Not the fastest rate of growth, if you compare it to ‘Comtesse de Bouchaud’ or ‘Azur Ball’ – even it feels a bit more vigorous.

The length of internodes is 12…18 cm. Leaves are triple, length with petiole – 14…18 cm, width – 15…18 cm, length of petioles – 5…7 cm. Leaflets are simple, elongated-ovate, with an elongated apex. Leaflets are 7…9 cm long and 3.5…4 cm wide. The length of petioles of central leaflets is 2…3 cm, lateral ones – 1…2 cm.

Flowers “Rouge Cardinal” on the shoots of the current year, flower stalks are formed on the top 5 nodes. Flowering usually begins in the second decade of July and can continue until the end of September. Flowers are simple, with 6 sepals, 10…15 cm across. Sepals are obovate or diamond-shaped, 5…7.5 cm long and 3.3…3.7 cm wide. The inner side of the sepals is dark red-purple, the middle band and the center at the base are slightly lighter. The outer side of the sepals are smoky red-purple. Stamens about 18 mm long, stamen filaments light purple-purple, anthers pale purple, bracts gray-purple.







Clematis ‘Rouge Cardinal’ – planting and care

Compared to many other clematis varieties, Rouge Cardinal is a bit capricious – it does not tolerate soil overwatering very well at all, it often catches spots on the lower leaves, it is slow to develop its root system – but it still lives. I think that if you like it outwardly (and almost everyone likes it, such luxurious dark red flowers are not often met), then it is definitely worth planting. You just have to approach it responsibly.

Choosing a planting site

South, east or west facing walls are suitable for planting ‘Rouge Cardinal’ clematis. If you are planting against a wall with a foundation, the clematis should be placed at least 50 cm away from it so that the roots do not freeze from the foundation in winter. The spot should be well-lit for most of the day, but slightly shaded in the heat of the afternoon – Rouge Cardinal does not tolerate the sun very well.

Clematis prefer light, highly humusified fertile soils with a reaction of the soil solution from slightly acidic to slightly alkaline. Large-flowered clematis are even more suited to slightly acidic, but it is also good for soil fungi that cause clematis wilt: that is why it is common for us to alkalize the soil.

When to plant clematis ‘Rouge Cardinal’?

HintThe best time for planting is August and September. During the remaining months before the cold weather, the clematis will have time to form a good root system and go into winter prepared. It can also be planted in early spring, before the shoots start to grow vigorously. From May until mid-August, it is better not to plant, but if you really need to, you can carefully transfer the plant with a lump of earth.


It happens that you bought ‘Rouge Cardinal’ late in autumn at a discount (often in late October garden centers are very discounted), and a day later the frost hits. What to do In such cases, you can cut the shoots to the first or second pair of buds and put the pot on the bottom shelf of the refrigerator. There it will remain until spring.

How to prepare a hole for planting clematis

Even for a small seedling, the pit should be prepared large, about 50x50x50 cm or slightly larger. In the first two or three years, the roots of the vines will only develop within the pit, so it is important that they have plenty of everything they need for growth within the pit.

If you have heavy clay soil, you should never put drainage at the bottom or fill the hole with looser soil: you will end up with a drainage well that will collect water from the entire surrounding area. “Rouge Cardinal” may not tolerate such soaking. The pit should be filled with a mixture of extracted earth and compost or humus in a ratio of about 1:1. You can also add a couple of tablespoons of superphosphate and potassium sulfate.

Do I need to clean the roots?

From purchased plants of unknown origin, it is better to expose and inspect the roots. Sometimes someone eats them right in the pot. Sometimes the roots have rotted and the rotted areas need to be cut off. After that, the root and the buried part of the stem should be covered with a mixture of river sand and ash to create a barrier for soil fungi, at least a weak one.

How to plant?

Set up by spreading the roots so they point out to the sides and downward. If the plant is young, with green stems, plant it the same way you received it, without burying it. If the stems are woody, you can bury them by 1-2 nodes when planting to get more shoots from the ground. Then sprinkle first with a mixture of sand and ash, and then with the prepared soil mixture. After that, water the plant thoroughly to remove any voids around the roots and add more soil – after planting, the soil is sure to settle.

Clematis Care


Water clematis only when there is a prolonged drought, infrequently but in large amounts at once. It is better to water with rain or pre-drained water under the root. After watering, the soil can be loosened to a depth of 1…2 cm and mulched.

Roaming the soil

It is better to loosen the soil to a shallow depth after every heavy rain or watering. This improves the air regime. Do not loosen deeply, because then you risk damaging the surface roots of the clematis.

Mulch the soil

Clematis ‘Rouge Cardinal’, and clematis in general, are very bad at overheating their roots. Mulching the root ball avoids overheating, reduces the number of weeds and simplifies maintenance.

It is better to cover the immediate area around the stem with a mixture of sand and ash to protect it from wilt. You can then mulch with hay, straw, grass clippings, neutralized peat. Over time, they will become an additional source of organic matter for the soil.

Сlematis ‘Rouge Cardinal’ Fertilizing

    1. In the spring, it is necessary to feed clematis with compost or humus in any reasonable amounts, as well as to apply nitrogen, phosphorus and potassium – 10, 5, 5 grams of active ingredient per plant.
    2. In the budding phase also requires feeding clematis. It is necessary to add 5 grams of nitrogen, phosphorus and potassium + micronutrients to the soil.
    3. At the height of the first wave of clematis blooms, feed the clematis again. Fill the soil with 5 grams of nitrogen, 5 grams of phosphorus and 5 grams of potassium, as well as macro and micronutrients. You can use a suitable compound fertilizer for clematis and other flowering garden plants, which you can find at your nearest store.
    4. In August for fertilizing clematis ‘Rouge Cardinal’ it is necessary to apply 5 grams of phosphorus and 5 grams of potassium per plant. You can also make foliar feeding with 0.5% solution of potassium monophosphate and microelements (about 0.25 g per 10 liters of water boric acid, magnesium sulfate, ammonium molybdate, etc.). Spraying is better in cloudy weather in the evening.

How to prune Clematis Rouge Cardinal

Clematis 'Rouge Cardinal' stems after pruning

“Rouge Cardinal” is a clematis of the 3rd pruning group. In the fall, it should be cut at a height of about 20…30 cm above a pair of strong buds and cover this cut for the winter. It is not difficult: you can lay a couple of coniferous legs, a piece of lutrasil and a film on top, so that the whole construction is not flooded with water. It is necessary to leave a small vent on the side for ventilation. In such conditions clematis will perfectly overwinter. Some people do not cover it at all, but only cut and high perch. In principle, this is not a bad option.

Clematis ‘Rouge Cardinal’ reviews

      • Michigan, south of Detroit: “Rouge Cardinal” has been growing for twenty years and has become a huge bush with excellent blooms. Every year it is cut short and winters under snow.
      • Western border of Wisconsin: clematis grows for many years, is coppiced and covered with peat for winter. The flowers are not red, but very dark red with a slightly violet tint, not large.
      • Tacoma: this variety of clematis was very successful. It is very unpretentious, abundantly blooms, color dark maroon, sometimes it seems a little purple.
      • New York: planted in the front garden two flowers Rouge Cardinal three years ago, both perfectly accepted and grow very lush, since 2 years. Very beautiful blooming, not many flowers yet, but they are beautiful.
      • South Dakota: Rouge Cardinal is one of the few clematis that overwinter without elaborate winter preparation, simply cut back, cover with peat and overwinter under snow.
      • Portland, Oregon: sometimes spots appear on the lower leaves of this clematis. Otherwise, the variety is very good, blooms beautifully every year, responsive to fertilizer.
      • Seattle: Compared to other clematis, Rouge Cardinal grows more slowly and blooms more modestly at first, but the color and texture of its flowers are excellent. It is worth to choose places that are well illuminated in spring and fall, in the penumbra this clematis develops poorly.

If you too have grown this clematis, please leave your feedback in the comments to the variety description. It will be useful to other readers of the website.

About the author

Fedor Fironov
Graduate of Plant Protection Faculty at GSAU. Main area of interest – clematis, peonies and perennials of Lamiaceae .

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