Agave macroacantha (Black Spined Agave): Growing and Care Guide

Looking for a new houseplant? Something to add visual interest to your home or office? We’ve got the answer for you: Agave macroacantha!

This guide will show you everything you need to know about growing and caring for one of these beauties. We’ll cover everything from light and temperature requirements, watering habits, soil types, ideal conditions for growth, and more!

About Agave macroacantha

Agave macroacantha is a beautiful, small, black-spined Agave. The leaves are green and toothed with an acuminate tip. It is slow growing and will reach up to two feet tall in its mature state.

Its thick, blue-gray leaves form a compact rosette. Each leaf terminates to a sharp terminal spine. This spine is brown or black and earned the plant its common name, Black Spined Agave.

The contrast between the dark-green leaves and the black spines is striking.

The flowers are typically green with purple markings. They appear at the top of a long stalk. These plants are slow growing and can take up to fifteen years to reach maturity.

Botanical Name	Agave macroacantha
Common Name	Black Spined Agave
Family	Asparagaceae
Plant Type	Succulent
Origin	Mexico
Maintenance	Low
Height	1-2 feet
Width	2-4 feet
Light	Full sun, Partial shade
Bloom season	Summer
Bloom color	Purple, Green
Water needs	Low
Soil	Well-Drained, Loamy, Sandy
Tolerant	Deer, Drought
Toxicity	Mildly-toxic
Hardiness (USDA)	8-11

Agave macroacantha Care

Agave macroacantha is an easy-to-care-for succulent well suited for indoor or outdoor use. This Agave is drought-tolerant once established and requires little watering, making it ideal for beginner gardeners.

Light

Agave macroacantha thrives in full sun. However, it is an adaptable plant that can take partial shade as well, especially if you grow it indoors or in a greenhouse.

Some afternoon shade may be necessary for areas with hot summers and intense sunlight to prevent the plant from getting sunburnt.

Soil

Agave macroacantha is happy in most soil types. However, it does best in sandy, well-draining soils that are slightly acidic to neutral.

Any soil will work fine as long as it drains well. You can amend regular potting soil with perlite or pumice to increase drainage and make it suitable for succulents.

Water

Agave macroacantha is a succulent plant that needs little water. Overwatering can cause rot, so letting the soil dry out between waterings is essential.

It’s best to water your Agave when the soil is bone dry (check by digging around with your fingers).

During hot summers, you might need to increase the watering cadence somewhat to combat the heavy evaporation. The reverse is true in the winter.

Temperature and Humidity

Agave macroacantha can tolerate a wide range of temperatures, but it’s best to keep it above 50 degrees Fahrenheit. The ideal range for Agave is between 55 and 75 degrees Fahrenheit.

If you want to overwinter your Agave, consider bringing the plant inside for the winter, as these plants are not particularly cold-hardy.

In addition to temperature, humidity is important for succulents. They don’t want to be kept in an overly humid environment because this can cause rot or mold.

Fertilizer

Agaves are very low-maintenance plants and don’t typically need fertilizer. However, if you want to fertilize, do so sparingly and only once a year in the early spring when plants are actively growing.

Slow-release, balanced fertilizers are the best solution for these types of plants.

Pruning

Agaves don’t need to be pruned, but it can be done if you want to control their size or shape.

You can cut off a few leaves around the outer rim of the rosette and then wait for new ones to grow back in their place.

This is best done during spring when the plant is actively growing.

Potting and Repotting Agave macroacantha

Agave macroacantha are hardy plants that can be left in their pots for years. They don’t need repotting unless they become too big or if you want to change the size or type of pot.

The best repotting time is when the plant is actively growing in the spring. However, you can also repot in early fall to encourage new growth before winter sets in.

Prepare

How to Repot (Step-by-Step)

1. Remove the Agave from the old pot.
2. Loosen up the roots with a garden spade or shovel.
3. Separate the topsoil from the root ball using your delicate tools and remove any dead leaves.
4. Place a layer of gravel or rocks on the bottom of your new container to improve drainage and aeration.
5. Fill up with the pre-selected potting soil and plant your Agave in it.
6. Water to help the plant settle in.

Propagating Agave macroacantha by Seeds (Step-by-Step)

1. Prepare your soil. You will need to use a sterile potting mix with no chemicals or fertilizers added.
2. Plant the seed below a thin layer of well-draining soil in a shallow pot.
3. Put down the container in a sunny spot and water it until the soil is moist but not soggy.
4. Allow at least one month for germination to occur before transplanting the seedlings into larger pots or directly into the ground.

Propagating Agave macroacantha by Offsets (Step-by-Step)

You can also propagate Agave macroacantha by offsets that appear around the base of the mother plant. To do this:

1. Remove a healthy offshoot from the mother plant.
2. Allow it to callus over for a few days and let the wounds heal.
3. Plant it in moist soil in a pot or directly into the ground.
4. Water regularly until established.

Blooms

Agave macroacantha is monocarpic, meaning that it only blooms once before dying. After the plant has flowered, it will die back to ground level and produce offsets around its base. These offsets are the new plants that will continue living after the parent plant dies.

Small, green, and light purple flowers are borne on a 6-foot-tall spike that rises from the center of the rosette. Only mature plants bloom, and usually only after 10-15 years have passed.

Toxicity

Agave macroacantha is mildly toxic. The plant sap causes skin irritation and dermatitis in sensitive individuals.

NOTE: This page is not intended as a substitute for veterinary advice. The toxicity of an ingested substance varies depending on the amount ingested, the animal’s weight, and its sensitivity to specific allergens. Contact your veterinarian or local animal poison control center immediately if you think your pet may have ingested a toxic substance.

Common Pests

Agave snout weevil

Agave snout weevil is the most common pest of Agave macroacantha. This small beetle burrows into the plant, causing damage to the stem and root system. The adult weevil lays her eggs around the plant, multiplying their number. When hatched, the larvae bore into new plants and fed on their sap.

Scale Insects

Scale insects are small, immobile insects that feed on the plant’s sap by sucking it out. They are usually found on stems and leaves but can also be seen on the surface or emerging from wounds.

You can rub neem oil on the affected parts to deal with them.

Slugs and Snails

Slugs and snails are common for gardeners and can cause considerable damage to your Agave macroacantha. They chew on the leaves and stems of your plants, leaving holes behind them. Use traps to bait and catch them.

Common Problems

Agave macroacantha (Black Spined Agave):Best Care Tips (Video)

FAQ