Clematis are deciduous climbing vines that produce colorful, scented flowers throughout the year. Clematis flowers have rich meaning and symbolism and also attract pollinators. However, producing such vibrant, exquisite flowers requires a lot of energy, which you can provide using fertilizer. In this article, we’ll explain when and how to fertilize clematis to get the best flowers.

How to Fertilize Clematis for Optimal Blooming

When and How to Fertilize Clematis – The Essentials

Fertilize clematis from early spring until the flowers appear. Avoid fertilizing once flowers emerge, as this reduces bloom time. Resume feeding after flowering has finished to encourage more flowers. Feed clematis every 4 to 6 weeks with high-potassium fertilizers such as bone meal or tomato feed.

Botanical Overview

Scientific Name:Clematis spp.
Native Range:Parts of the Northern Hemisphere, including Asia, Europe, and North America
Growing Zones:USDA Zones 4 to 9
Flowering Season:Late winter until late fall, depending on the species
Colors:Blue, pink, purple, red, yellow, white, green

About Clematis

About Clematis

The Clematis genus belongs to the buttercup family (Ranunculaceae) and contains approximately 300 species. Clematis are fast-growing deciduous or evergreen plants with climbing vines and woody stems. Clematis are indigenous to cool, temperate parts of the Northern Hemisphere.

All types of clematis are divided into three main groups depending on when they flower. This also governs when each species of clematis needs to be pruned.

  • Group 1 Clematis are early-flowering species that bloom in late winter or spring.
  • Group 2 Clematis typically have large, showy flowers and bloom in spring and summer.
  • Group 3 Clematis are late-flowering varieties that bloom from summer until fall.

Clematis can also be divided between large-flowered clematis and small-flowered clematis. There are several types of small-flowered clematis, such as Armandii, evergreen, herbaceous, Nelly Moser, and Montana clematis.

The Role of Fertilizer in Plant Health, Growth, and Development

The Role of Fertilizer in Plant Health, Growth, and Development

Plants need four main types of nutrients; structural macronutrients, primary macronutrients, secondary macronutrients, and micronutrients.

Carbon (C), hydrogen (H), and oxygen (O) are the structural macronutrients. These vital building blocks come from air and water absorbed by plants through their leaves or roots. These structural macronutrients are used to manufacture glucose and cellulose to create new plant tissue, which enables growth.

Plants also absorb three primary macronutrients from the soil; nitrogen (N), phosphorus (P), and potassium (K). Nitrogen helps produce bushy foliage and the chlorophyll needed for photosynthesis. Phosphorus is an important nutrient for flower production, while potassium helps the plant circulate water, nutrients, and minerals.

Secondary macronutrients are minerals that also help plants grow and develop. These minerals include calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), and sulfur (S).

Different Types of Fertilizers

Fertilizers are divided into two groups; organic fertilizers and synthetic fertilizers. Both types of fertilizers are usually sold as either liquid feed or slow-release granules.

Organic fertilizers need to be broken down by organisms in the soil before the plant can use them. These fertilizers are made from natural ingredients, making them more environmentally friendly than synthetic fertilizers. Common organic fertilizers include compost, blood meal, bone meal, manure, and worm castings.

Synthetic fertilizers don’t need to be broken down in the soil, so plants can access nutrients instantly. But although synthetic fertilizers work faster than organic ones, they are less environmentally friendly. Synthetic fertilizers are made using chemicals and salts that leach into the soil, killing beneficial bacteria and reducing soil quality.

All fertilizers use NPK ratios to help you determine how much nitrogen, phosphorus, and potassium each fertilizer contains. Use nitrogen-rich fertilizers if you want lots of bushy foliage, especially if you’re growing leafy vegetables like kale. If you want your plants to produce lots of flowers, choose fertilizers with higher amounts of phosphorus.

Signs That Your Clematis Is Lacking Nutrients

Signs That Your Clematis Is Lacking Nutrients

Flowers Do Not Appear

If your clematis struggles to flower, it may be due to a lack of nutrition. Clematis need fertile, well-draining soils that contain plenty of phosphorus to produce flowers. Add organic matter such as compost to increase the nutrient content of the soil and fertilize regularly.

A nutrient imbalance within the soil could also cause the lack of flowers. If the soil contains too much nitrogen, your clematis will focus on producing lots of bushy foliage at the cost of flowers. To address this imbalance, use a high-phosphorus fertilizer such as bone meal or tomato feed.

Symptoms of Disease

Clematis vines can suffer from various fungal diseases, such as clematis wilt and powdery mildew. If your clematis doesn’t get adequate nutrition, then it can be more vulnerable to fungal infections.

When and How Often Should You Fertilize Clematis?

When and How Often Should You Fertilize Clematis?

Clematis should be fertilized every 4 to 6 weeks during the growing season. Begin feeding your clematis in early spring and continue until the first flowers start to emerge. Avoid fertilizing while the plant is in bloom because over-fertilizing can reduce the duration of the flowers.

Once your clematis has finished flowering, resume feeding once per week until mid-fall. This should encourage your clematis to produce another round of flowers before winter sets in. Use a high-phosphorus fertilizer to achieve optimal flower production.

Clematis that are growing in pots should be fertilized slightly differently than plants growing in the ground. Add slow-release fertilizer granules to the soil in the container two or three times during the growing season. Use high-phosphorus granules to promote flowering.

The Best Fertilizer for Clematis

The Best Fertilizer for Clematis

High-phosphorus fertilizers are ideal for clematis because phosphorus helps produce more flowers. Choose fertilizers that have an NPK ratio of 5-10-5 or 5-10-10. Remember that fertilizers containing too much nitrogen will produce bushy foliage at the expense of flowers.

Choose organic high-phosphorus fertilizers wherever possible, as synthetic fertilizers can contain harmful chemicals. Bone meal is a good choice because it’s widely available and gets absorbed quickly. Liquid tomato feed can also work well because the extra potassium will supplement flower production.

Always follow the packet instructions to avoid over-fertilizing your clematis.

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How to Apply Fertilizer

How to Apply Fertilizer

The method of applying fertilizer changes depending on the type of fertilizer that you’re using. Slow-release granule fertilizers can simply be dug into the soil at the start of the growing season. However, liquid fertilizers are the most common type. Here’s a quick guide to applying liquid fertilizer to your clematis:

Choose high-phosphorus liquid fertilizers with NPK ratios of 5-10-5 or 5-10-10.

Dilute the fertilizer according to the instructions on the packet. Add the recommended dose to an empty watering can before topping up with the recommended amount of water.

Apply the fertilizer as if you were watering the plant. Pour the diluted fertilizer around the stem of your clematis. Take care to avoid splashing any fertilizer on the leaves.

It’s also worth noting that all parts of the clematis plant are considered poisonous, so it’s prudent to wear protective gloves when overseeing any form of care with these plants.

Key Considerations

Key Considerations

While fertilizers can help clematis vines produce more flowers, too much fertilizer can do more harm than good. Here are a couple of things to consider when fertilizing clematis.


Giving your clematis too much fertilizer can cause problems – especially if you’re using synthetic fertilizers. Many fertilizers contain chemicals and salts that can build up in the soil. Always follow the instructions on the packet and only apply the recommended dosage each time.

Soil Type

Clematis need fertile, well-draining soils that contain lots of nutrients, such as loamy or silty soils. If you’re using nutrient-poor chalky or sandy soils, you may need to fertilize more often. Alternatively, you can add some compost, organic matter, or bone meal to these soils to improve nutrients.

Fertilizing Clematis FAQs:

Do Clematis Need Fertilizer?

Clematis grow quickly and need lots of nutrients, so fertilize them regularly throughout the growing season.

Fertilize clematis once every 4 to 6 weeks from early spring until flowers start to emerge. Stop fertilizing while flowers are blooming, then resume once flowering has finished. This can yield a second flush of flowers in the fall.

High-phosphorus organic fertilizers like bone meal are ideal for clematis. Choose fertilizers with NPK ratios similar to 5-10-5 or 5-10-10.

Wrapping Up

Clematis are fast-growing climbers, requiring lots of nutrition to fuel their growth. Start fertilizing clematis in early spring and feed every 4 to 6 weeks until the flowers emerge. Then stop fertilizing until flowering has finished. You can then start feeding again to get more flowers. Use high-phosphorus fertilizers to get as many flowers as possible.

Contributing Editor | Full Bio | + posts

Edd is a budding content writer and gardener living in the United Kingdom. He has a bachelor's degree in Creative and Professional Writing and has written for several gardening publications online. He is passionate about nature and sustainability with a focus on gardening and wildlife.

Author Edward Hodsdon

Edd is a budding content writer and gardener living in the United Kingdom. He has a bachelor's degree in Creative and Professional Writing and has written for several gardening publications online. He is passionate about nature and sustainability with a focus on gardening and wildlife.

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