What is the Best Fertilizer for Clematis? A Comprehensive Guide

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.

It is important to use a low nitrogen fertilizer in the spring when you feed your clematis. Clematis plants need a lot of food, but too much nitrogen makes the leaves grow too much instead of flowers. The best fertilizer for this ratio is one that has more phosphorus and potassium, like 5-10-10. This gives the clematis the right mix of nutrients to help it flower.

This complete guide will tell you everything you need to know about feeding clematis to get lots of blooms.

When to Fertilize Clematis

Timing is crucial when fertilizing clematis. Use fertilizer early in the spring, when buds are about 2 inches long. This will encourage flower growth instead of leaf growth. Once the first flowers open, stop fertilizing so the plant can bloom for as long as possible.

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

• In the spring, use a fertilizer like 5-10-10 that is high in phosphorus and low in nitrogen. 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.