Do Barrel Cactus Need Nurse Plants?

Barrel Cactus Seedlings

• Barrel cacti have large but very shallow root systems that must be protected until they are established. Young barrel cacti can't survive on their own without establishing a root system; full exposure to the desert sun would quickly kill them before that happens. Young cactus roots require some sort of protection. If you wish to grow barrel cacti in your desert garden, try pairing the seedlings with a native bursage shrub.

Ironwood Trees

• Ironwood trees are one of the few tall trees that grow in the desert. Ironwood is found only in the Sonoran Desert. It is extremely valuable as a barrel cactus nurse plant, as it enriches and cools the soil in its shade. According to Pima County, Ariz., the presence of the ironwood tree creates a micro-habitat sheltering young succulent plants and wildflowers from direct sunlight, as well as providing lower surface temperatures, more organic matter from its decomposing fallen leaves and protection from hungry desert herbivores.

Bursage

• Bursage is a desert plant with a broader range than ironwood. Bursage is a shrub whose branches form a overarching crown, protecting the young plants underneath. Where larger trees or shrubs are not present, bursage may be the dominant nurse plant in its area.

Growing Up

• Once a barrel cactus has established its own root system, it no longer requires the moisture or shade that the nurse plant provides. Larger cactus species may eventually sap the nutrients and water from the nurse plant, causing it to fail and die, but the barrel cactus doesn't grow as large a saguaro cactus, for example, and is able to coexist with its nurse plant. Similarly, as young barrel cacti in the garden grow up, they can withstand more afternoon sun than when they were young.