All you need to know about planting, growing and caring for clematis in our detailed Grow Guide.
Clematis are popular perennial climbers, providing height and colour throughout the season. They look particularly good with roses. Theres a huge variety of clematis to grow, with flowers ranging in size from small bells to large dinner plates.
Clematis can be good for wildlife, clothing walls, fences and trellis with leaves and flowers, which provide shelter for insects and sometimes birds. Some clematis flowers are visited by pollinators, while the fluffy seedheads of Clematis tangutica cultivars may be used as a nesting material by house sparrows.
Clematis are popular climbing vines that produce incredible, colorful blooms. However, getting your clematis to reach their full flowering potential requires providing the right nutrients at the right time. Choosing the best fertilizer for clematis is key to maximize blooms each season.
When fertilizing clematis, it’s important to use a low nitrogen fertilizer in spring. Clematis are heavy feeders but too much nitrogen leads to excessive foliage growth rather than flowers. The ideal nutrient ratio is a fertilizer higher in phosphorus and potassium, such as 5-10-10. This provides clematis the right balance of nutrients to fuel flowering.
In this comprehensive guide we’ll cover everything you need to know about fertilizing clematis for prolific blooms
When to Fertilize Clematis
Timing is crucial when fertilizing clematis. Apply fertilizer in early spring when buds are around 2 inches long This stimulates blooms rather than leafy growth. Stop fertilizing once the first flowers open to avoid reducing bloom time
Resume fertilizing after the initial flowering to encourage a second flush of blooms before winter. Fertilize established clematis every 4-6 weeks from early spring until mid-fall.
How to Fertilize Clematis
-
Use a high phosphorus, low nitrogen fertilizer like 5-10-10 in spring. Too much nitrogen causes excess foliage over flowers.
-
Apply fertilizer evenly around the base of the plant. For container plants, mix fertilizer into the potting soil.
-
Water fertilizer in well after application to avoid burn. Let soil dry between waterings.
-
Fertilize 4-6 weeks apart from early spring until flowers emerge. Resume after flowering until mid-fall.
Best Fertilizers for Clematis
Organic Fertilizers
-
Bone meal – Provides a slow release of phosphorus to stimulate blooms.
-
Compost or manure – Improves soil structure and nutrients for better growth.
-
Worm castings – Introduces beneficial microbes and micronutrients.
Chemical Fertilizers
-
Tomato feed or flower fertilizers with low nitrogen and higher potassium and phosphorus.
-
Balanced 10-10-10 fertilizers can be used alternately through the season.
-
Soluble fertilizers like Jack’s Blossom Booster 10-30-20 provide a growth boost.
Slow Release vs Liquid Fertilizer
-
Granular fertilizers provide longer term, steady feeding over 2-3 months. Less risk of burn.
-
Liquid fertilizers deliver fast nutrients but require more frequent applications like every 2-4 weeks.
Application Methods
-
Mix granules into soil around plants. Reapply per instructions, usually every 2-3 months.
-
Dilute liquid fertilizers and apply around plant roots. Reapply every 2-4 weeks.
-
Insert spikes into soil for slow nutrient release every 4-6 weeks.
Signs Your Clematis Needs More Fertilizer
Underfed clematis may exhibit:
-
Lack of flowers or few, small blooms.
-
Sparse, weak foliage growth.
-
Yellowing leaves indicating nutrient deficiencies.
-
Increased susceptibility to fungal diseases.
-
Stunted growth and dieback.
Clematis Fertilizing Tips
-
Test soil pH and amend to 6.5-7.0 range if needed.
-
Use compost and mulch to enrich soil nutrients and moisture retention.
-
Water regularly to keep soil moist, not soggy, for proper nutrient uptake.
-
Alternate between granular and liquid feed for balanced feeding.
-
Apply at half strength rates until plants are established.
-
Stop fertilizing after planting and don’t overfeed.
-
Watch for signs of fertilizer burn like brown crispy leaves.
-
Reduce frequency for container plants depending on size.
-
Consider foliage size and growth rate when determining feed rate.
Common Clematis Fertilizing Mistakes
-
Using high nitrogen fertilizer leading to all leaves, no flowers.
-
Overfertilizing causing fertilizer burn and root damage.
-
Feeding too late in the season resulting in weak winter preparation.
-
Applying at full strength rates on young or stressed plants.
-
Forgetting to resume fertilizing after initial flowering period.
-
Failing to regularly test and amend soil pH before fertilizing.
-
Neglecting consistent watering so plants can’t absorb nutrients.
-
Not adjusting frequency for container versus in-ground plants.
FAQs About Fertilizing Clematis
How often should clematis be fertilized?
- Feed clematis every 4-6 weeks from early spring to mid-fall. Avoid fertilizing when in bloom or dormant.
What is the best fertilizer ratio for clematis?
- Aim for fertilizers with more phosphorus and potassium than nitrogen, like 5-10-10 or 5-10-5.
Should I fertilize clematis in the first year?
- Yes, fertilize lightly starting when buds emerge in spring. Reduce strength until established.
Can I use Epsom salts as fertilizer for clematis?
- Epsom salts provide magnesium, sulfur, and oxygen to help clematis absorb nutrients. But use sparingly.
Is bone meal good for clematis?
- Yes, bone meal provides an excellent slow release source of phosphorus for great blooms.
Should I prune clematis before fertilizing?
- Prune first, then fertilize once new growth starts to stimulate buds and flowering.
The Bottom Line
Fertilizing clematis properly is essential to maximize flower production from these hungry vines. Use a low nitrogen, high phosphorus fertilizer in early spring when buds emerge. Feed every 4-6 weeks, avoiding periods of bloom or dormancy. Stick to organic options where possible and watch for signs of overfeeding. With the right fertilizer and care, your clematis will reward you with endless flowers.
Growing clematis: problem solving
Clematis wilt can cause huge problems for clematis, growers, causing clematis to die suddenly without apparent reason. Larger flowered types are the most likely to be affected. It’s easy to spot as plants quickly wilt. Clematis wilt is a fungal disease. Prune out all affected stems and burn them.
Clematis are also prone to an attack from earwigs, which chew holes in the flower petals. This damage is only cosmetic and doesnt harm the plant. If youre really concerned you can create earwig traps by pushing a 1m long cane into the ground next to the clematis. Stuff a plastic plant pot with straw and place it upturned on the top of the cane. Earwigs will use this as shelter during the day, giving you the opportunity to catch and rehome them.
Rabbits, mice, slugs and snails may also be a problem. Protect young plants to give plants a good start.
Choosing the right clematis
Theres such a wide variety of clematis available, that its important you choose the right clematis for the spot you want to grow it in. Some clematis, such as Clematis montana, are extremely fast-growing and vigorous, and are suitable for covering an unsightly wall or shed in a short space of time. Other clematis have a much less vigorous growth habit, and are therefore suitable for growing in pots – look for growth habit on the label or varieties such as Clematis ‘Blue Dwarf’, which indicates a less vigorous habit.
Ther are plenty of clematis varieties suitable for sun and shade, so again check the label to see how well suited your clematis is to the spot you have in mind.
Lastly, consider how much care you want to give your clematis. If youre happy pruning your clematis annually, then Group 3 clematis are perfect for you. However, if youd like to keep pruning to a minimum then opt for a Group 1 or Group 2 clematis.