Agave salmiana 'Green Giant' in Austin, TX

Agave salmiana 'Green Giant' is a large agave, typically about 6 feet tall and wide in nursery listings, with a large terminal spine and strong teeth along the leaf edges. Once established it tolerates dry conditions, but overwatering rots its roots. It is rated hardy to about 16°F when kept dry, so Austin's hard freezes are a real risk. Give it generous room and keep it away from walkways and play areas.

Each plant is a rosette of thick, fleshy leaves. The leaves end in a large terminal spine, and the edges carry strong teeth. Leaf color ranges from gray-green to bright green. Over time, the plant produces many suckers, called offsets, that can form a large colony.

Wear gloves and eye protection when you work near it. The spines are sharp, and the sap can blister skin.

• Once established: It is drought tolerant and needs little supplemental water.
• Between waterings: Let the plant dry out before watering again.
• Winter: Keep the soil dry. Winter wet is a common cause of rot.
• Overwatering: Too much water rots the roots, which is the bigger risk.

Give it full sun and a gritty, fast-draining mix. Gravel beds and xeriscapes work well, like the bed in these photos, which has prickly pear cactus behind it. In a container, choose unglazed clay so excess moisture can evaporate, and use a pot large enough for the plant's eventual size. Our guides on cold-hardy agaves and pink fairy duster cover companion plants for the same kinds of beds.

Because of its size and terminal spines, keep it well back from paths and play areas. A common guideline for large spiny agaves is at least 6 feet from walkways. The suckers can crowd a bed quickly, so plan the spacing at planting time and remove offsets that encroach on their neighbors.

Agave salmiana 'Green Giant' is rated hardy to about 16°F when kept dry. Austin's hard freezes can drop below that, and Texas winters run colder than the plant's native Mexican climate, where lows rarely fall below about 25°F. Protect young plants during hard freezes, and keep the soil dry through winter.