Growing Purple Clematis (Clematis Viticella) Indoors & Outdoors

Last Updated on October 31, 2021 by Phil

The Clematis viticella is commonly known as the purple clematis. Although, it also has a few other common names including Italian clematis, Italian leather flower and Virgin’s bower.

As you would guess it is called purple clematis because of its color. But, it is important to note that it is a group of clematis flowers including hybrids. As such, there are many other colors with purple being the most well known.

As such, you’ll see them in hues of red, blue and purple during the summer. And, blue, red and purple come fall. These plants are also known for blooming for long periods of time from mid summer all the way until fall.

Like many other clematis, this is a vigorous climber. It can grow to between 10 and 15 feet high covering a spread of 3 to 5 feet side to side. This makes it a great option if you want a plant with colorful flowers for decorating or covering garden structures like arbors, trellises and pergolas. It works just as well for fences and walls.

Table of Contents

Clematis Viticella Plant Care

Clematis Viticella Light

As with other plants of this genus, the Clematis viticella likes a lot of sun. And, like is brethren, it prefers exposure to be on its top side while keeping its roots cool.

Thus, the best light conditions for it is both full sun and part shade depending on where you live and what location you place it.

To explain,

If you live in a cool climate area, then giving the plant full sun is best. That means at least 6 hours of direct sunlight on a daily basis.
If you live in a warmer region, it is better to give it partial shade, especially in the mid afternoon and peak of summer when the sun’s rays are most intense.

Whichever you belong to, always remember to keep its roots cool. To do so, it is best to keep it away from lots of sunlight. This can be by using some kind of shade from other plants or garden furniture. Or, you can add a layer or mulch, grow ground cover over its base or place rocks to cover it.

All of these methods work. So, you can opt for the easiest one for you.

The other part of the equation is where you situate the plant in your garden, outdoor space (like patios, decks, etc) or home.

Facing east receives gentle morning and indirect afternoon sun. As such, you don’t have to worry a lot about long hours of exposure.
If it is placed in the west or south, you’ll want to provide similar kind of shade described above because it both these locations get brunt of the mid-afternoon sun which is when it is most intense.
North facing positions aren’t idea, although doable depending on where you live, because there’s less light there.

Clematis Viticella Temperature & Humidity

The purple clematis is hardy to USDA zones 4 to 8. That means they can survive outdoors all year round when the lowest temperature in your region is -30 degrees Fahrenheit. They are tough plants that can withstand some frost.

Because they’re partial to the cold, they don’t like temperatures going above 20 degrees Fahrenheit as well.

If where you live happens to have climates outside of this range, you can opt to grow them in containers or planters. This will allow you to move them when the weather outside gets too cold or warm.

Keep in mind that the plant does grow in size, reaching up to 15 feet high outdoors. While its size is much more manageable in containers, it can still pose a space and ceiling challenge.

Also when growing clematis viticella, keep in mind that mulch is your best friend. It protects the plant from hot weather and improves moisture retention to prevent dehydration. In cold temperature, it works as insulation.

Depending which side you’re on and how hot or cold it gets, you cad add a thin or thicker layer of mulch.

Watering Clematis Viticella

The clematis viticella needs an inch or so of water every week. This is true for other clematis vines as well. While the plant isn’t a heavy drinker, watering is one aspect where you want to give it enough.

As such, keep a eye out on the soil during the warm, dry months to make sure that the soil is kept moist during this period. In general, you’ll likely need to water the plant once a week during this time.

Although, it’s always better to actually check the soil. Similarly, you can get a rain gauge, which is very inexpensive. That way, it is easy to keep track of how much rainfall there has been the past 7 days or so and water (or not) as needed.

You want to deep water it each time you add moisture. This will allow the liquid to reach its roots. Watering in the morning is a good way to keep too much of the moisture from evaporating. It also gives the plant enough time to dry because there is sunshine for the rest of the day.

Also, use mulch to help with moisture retention. You can replenish it every spring to keep it fresh.

That said, be aware that the clematis viticella is susceptible to moisture problems including clematis wilt, powdery mildew and other fungal problems. To prevent this from happening, good air circulation is key as it helps excess moisture dry.

Soil

The clematis viticella enjoys moist, well draining soil. For this vine, drainage is the most important thing when it comes to soil. As such, it goes hand in hand with the section above on watering.

The reason for this is that the plant can pretty much tolerate different kinds of soil as long as it drains well.

That said, for the best results, you also want to keep soil pH to above 6.0. it likes neutral to alkaline soil.

As with other clematis, this is a climber. Because it grows to between 10 and 15 feet high, it is well suited for tall structures like trellises, high fences and arbors. In contrast, smaller clematis can be set up with shorter poles.

Fertilizing

Purple clematis does best when given low nitrogen fertilizer. A 5-10-10 or 5-10-5 plant food works really well as the nitrogen is lower than the phosphorus concentration.

The reason for this is that nitrogen helps plants’ leaves grow. Thus, high nitrogen fertilizer is good for lawns and foliage plants. If you use them on flowering vines like the clematis viticella, you’ll end up encouraging more leaf growth and less flowering.

So, you end up with lackluster blooms and in all likelihood fewer of them.

What you want instead is low nitrogen and higher phosphorus. Phosphorus is the P in the N-P-K ratio. It is also the second number in the trio. This nutrient is that encourages flowering. Thus, having a higher concentration improves blooming.

As always, it is a good idea to have your soil tested before you grow your plants. This will let you know what your soil’s pH level is and what nutrients it is rich and poor in. That way you know which to supplement when needed and which minerals to back off of.

Pruning Clematis Viticella

The clematis viticella belongs to pruning group 3. This means it sprouts new flower buds on new wood. As such, you want to aggressively prune it early n the spring. You can trim back the stems all the way until they are between 6 to 12 inches from the ground.

Don’t worry when doing so because it will grow up come late spring or summer. The plant is a fast grower so this isn’t a problem.

Propagation

Clematis viticella can be propagated via stem cutting and layering. Of the two, cuttings are much easier which is also why more gardeners choose this option.

How to Propagate Clematis Viticella from Stem Cuttings

Choose a stem that’s between 4 to 6 inches long. You want to pick a soft wood cutting. That is, one that’s still soft (fresh) and just turning brown as opposed to the stiff, brown hard wood. Also, make sure you get a healthy stem with at least a few leaves on it.
Cut the stem using a sterilized pair of scissors or pruning shears.
Plant it in a container with fresh, well draining potting mix.
The cutting will take about one to two months to root. As such, patience is key.
To help it along, keep in somewhere there’s high humidity and bright, indirect light.
Water to keep the soil moist

source: wikimedia commons

Clematis Viticella Transplanting & Repotting

When planting or transplanting clematis viticella, you want to make sure to choose the right location. Of course, you can also grow it in a pot or planter which allows you to control the conditions a little better. However, the plant won’t be able to grow and spread out as much in a container. As such, you won’t be able to appreciate its full glory.

That said, here are a few things you need before planting your clematis viticella.

Choose a spot that gets more than 6 hours of direct sunlight daily. If you live in a warm region, partial shade will be a better option.
Keep the roots cool. You can use mulch or grow ground cover around the plant to protect its base from the sun. You can likewise use rocks or other objects to cover it.
Moisture retentive, well-draining soil. Yes, it’s an oxymoron. But, you need soil that’s able to hold enough water to keep the plant hydrated. But, well draining enough so that excess moisture is also drained away. The best soil for this is loamy soil or one that’s been amended with compost. While the clematis viticella can tolerate different soils, excess moisture can introduce fungus, root rot and wilt. All of which are bad.
Have a vertical structure nearby. This will allow the plant to climb up and grow onto something.

Once you have these ready, it’s time to dig.

When digging, make sure the hole is big and deep enough. You will need to plant the root ball 2 to 3 inches under the soil surface so that new shoots grow from under the ground.

Toxicity

As beautiful as the plant is, it is important to keep children and pets away from it. The plant contains protoanemonin, which is toxic to both people and animals including dogs, cats and horses.

When ingested it will cause mouth irritation as well as ulcers. Other symptoms also include diarrhea, vomiting and drooling.

Similarly, you’ll want to wear gloves when handling it because it causes skin irritation for some people.

Pests and Diseases

Clematis viticella are susceptible to powdery mildew, root rot and clematis wilt. All of which are moisture related. That is, overwatering or allowing moisture to sit too long be in on the soil or its leaves are problematic for the plant.

As such, it is a good idea to stay on top of your watering routine. Making sure that the soil is well draining is the best way to avoid many problems including root rot and clematis wilt. Also providing the plant with good air circulation lets it dry off quickly when wet.

As for pests, aphis, slugs, snails and caterpillars will come visit. You’ll likewise need to deal with earwigs and whiteflies.