Trumpet Vine Feeding: Learn When And How To Fertilize Trumpet Vines

Pink-Orange Flowered Trumpet Vines
trumpet vine fertilizer
(Image credit: stevebphotography)

Plants called "trumpet vine" are usually those scientifically known as Campsis radicans, but Bignonia capreolata also travels under the common name of its cousin trumpet vine, though is better known as crossvine. Both plants are easy to grow, low care vines with bright, trumpet-shaped flowers. If you are growing these flowers, you will need to understand when and how to fertilize trumpet vines. Read on for information about how and when to fertilize a trumpet vine.

Trumpet Vine Feeding

Trumpet vines thrive in USDA plant hardiness zones 4 through 9. Generally, the vines grow fast and require a strong structure to keep them where you want them to be. Most soil contains sufficient nutrients for trumpet vine plants to grow happily. In fact, you are likely to spend more time trying to keep these vines a manageable size than worrying that they aren’t growing fast enough.

When to Fertilize a Trumpet Vine

If you notice that the trumpet vine’s growth seems slow, you can consider fertilizing trumpet vine. If you are wondering when to fertilize a trumpet vine, you can start applying fertilizer to trumpet vine in the spring if the low growth rate warrants it.

How to Fertilize Trumpet Vines

Start fertilizing trumpet vine by sprinkling 2 tablespoons (30 ml.) of 10-10-10 fertilizer around the root area of the vine. Be careful of overfertilizing, however. This can prevent flowering and encourage the vines to grow aggressively. If you do see excess growth, you should prune back trumpet vines in the spring. Cut the vines so that the tips are no more than 12 to 24 inches (31-61 cm.) above the ground. Since trumpet vines are the type of plant that produces flowers on new growth, you do not have any risk of destroying next year’s blossoms by pruning in spring. Rather, a hard pruning in spring will encourage lush growth at the bottom of the plant. This will make the vine appear healthier and allow for more flowering during the growing season.

Fertilizing Trumpet Vines Won’t Necessarily Help the Plant Flower

If your trumpet vine isn’t flowering, you need to have patience. These plants must reach maturity before they blossom, and the process can be a long one. Sometimes, vines need five or even seven years before they flower. Pouring fertilizer for trumpet vines on the soil won’t help the plant flower if it is not yet mature. Your best bet is to make sure the plant is getting direct sun every day and avoiding high nitrogen fertilizers since they encourage foliage growth and discourage blossoms.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.