Power Plants for Pollinators

By Shaun McCoshum, Ph.D, member at large

Pollinator plants: you hear that term used a lot, and generally with no explanation. So, what makes a plant good for pollinators? The easy answer is any plant that benefits a pollinator species is a pollinator plant. However, some plants provide more benefit than others. Pollinators rely on plants in a few different ways.

Most pollinators need to feed on nectar and/or pollen, with a few exceptions where pollinators use flowers for hunting or thermoregulation. Some pollinators also need host plants to feed their young as we see with many insect groups including butterflies, moths, and various beetles. This means that some plants are labelled “pollinator plants” because they provide either nectar or pollen food for pollinators, and some plants get the label because they are a larval host plant for a pollinator species.

Let’s talk about the flowering species that provide nectar. Nectar is the sugary liquid secreted by nectaries which are on a wide range of flowers. Bats, hummingbirds, bees, butterflies, beetles, flies, wasps, and many other insect species all consume nectar. Flowers produce nectar to attract pollinators so that pollen can be attached to animals and then carried to another plant to assist with plant fertilization.

It’s important to know that flowers will sometimes cheat the system, with some specimens providing much less nectar than other plants of the same species. Nectar cheats are part of the reason some gardeners will notice pollinators not visiting a plant known to attract pollinators. Flowers will also modify how much nectar they produce based on growing conditions, with stressed plants usually producing less nectar than plants growing in the right conditions.

For pollinators, the amount of nectar a flower produces is just as important as how the nectar is presented. Hummingbirds, bee flies, and hawk moths can access nectaries in long tubed flowers like Cardinal Flower (Lobelia cardinalis), Coral Honeysuckle (Lonicera sempervirens), Mock Vervains (Glandularia spp.), Phloxes (Phlox spp.), and Trumpet Vine (Campsis radicans). Short-tubed flowers like Beebalms (Monarda spp.), Devil’s Bouquet (Nyctaginia capitata), Lantana (Lantana spp.), and Larkspurs (Delphinium spp.), have flower shapes that allow many butterflies, long tongue bees, and moths to access their nectar.

In contrast, many disc and ray flowers in the Sunflower Family (Asteraceae), large cup flowers common in the Cactus Family (Cactaceae), and some of the flowers in the Dogbane Family (Apocynaceae) provide nectar to insects with shorter tongues including short-tongue bees, bats, mantises, umbrella wasps, spider wasps and Tachinid Flies. The shape of flowers also allows some pollinators to crawl into the flower to access nectar like Desert Willow (Chilopsis linearis), Texas Sage (Leucophyllum frutescens), and various Beardtongues (Penstemon spp.).

Conversely, plants that are not great nectar producers include most grasses (Poaceae), docks (Rumex spp.), yuccas (Yuccas spp.), gourds (Cucurbitaceae), and nightshades (Solanum spp.).

At right is a list of some of our Texas native plants that are great nectar producers and beautiful in the garden.

Shaun McCoshum can be reached at mccoshsm@gmail.com.