^{(Photograph = Coral bean flowers, Lars Hammar)}

Introduction

Bottle plants have enlarged stems or roots, or both. If roots, you can expose the enlarged root-stem junction by removing the earth above the root. This is sort of like exposing the top half of a turnip, but in a woody plant the effect is more permanent and often beautiful. If the enlarged area is at the base of the stem/trunk, it is often called a caudex.

The Details

Erythrina herbacea (coral bean) is one of many Erythrina species. Coral bean is small and shrub-like, but some Erythrina species are  trees. Almost all have red (sometimes pink or purple) flowers. As a member of the pea-and-bean family, coral bean makes bean-like seeds, but they are red and poisonous.

Coral bean grows along the Gulf Coast from deep in Mexico to both sides of Florida. It is often found in seasonally moist plains and meadows, but once it has formed a large root/caudex it will withstand intense drought. Likely, plants with a large caudex will survive winter in an unheated garage.

Though from nearly frost-free areas, coral bean grows into USDA  zone 7. The branches die back in cold or drought, but the root survives and sprouts new shoots in the spring. In warm areas coral bean blooms in late April or May through June, the leaves follow the blooms.

E. flabelliformis is the desert counterpart to E. herbaceae, both withstand drought but E. flabelliformis is a true desert plant.

Additional Information: Erythrina herbaceae herbarium sheet