Echinocactus grusonii inermis
This article belongs to our "exotic pets and plants series" pages which do not focus on aquatic fish, but to other species that are often kept or grown by hobbyists. Feel free to share your experiences with this cactus at the bottom of this page!
Echinocactus grusonii inermis is a recent addition to the cactus family as it is actually a cultivar from the commonly more collected Echinocactus grusonii so it does not have a true family classification or a natural habitat where it could have originated from. It’s direct predecessor inhabits Central America and it is believed that this cultivar occurred by pure accident but it is becoming more common nowadays and is included in many cactus collections.
This cactus develops the typical barrel shape of the Echinocactus but it has a shorter body than Echinocactus grusonii but keeps the same radial spines that produces yellow spikes where the areoles occur. The main colouration is a pale green so do not worry that the cactus may look in ill health, this colouration is perfectly normal. Mature specimens can reach up to a height of 90 cm and mature specimens will produce basal shoots if cared for properly.
They are a very slow growing cactus so to reach maturity can take several years so patience is required and long term care will need to be provided to get the best from this plant.They are classed as a tender cactus and will not endure temperatures below freezing, they are best kept indoors or in a greenhouse that has heating supplied through the winter months. If kept in a greenhouse make sure that red spider mite does not invade as these will cause a lot of damage to the plant. Watering should also be administered carefully to prevent rotting, in the winter months it is best to keep this cactus dry but in the summer months it is advised to keep the cactus soil moist but never wet. It is also advised to apply a suitable cactus fertiliser during the summer months to promote growth but always use the recommended dosage.
Echinocactus grusonii inermis can be propagated by cuttings or seed, mature plants will produce basal shoots which can be separated from the mother plant but it is very important to allow these to dry out for a couple of weeks before planting into a suitable cactus soil. Water initially but never allow the soil to become soggy, moist soil will be perfect to promote root growth. Seeds can be grown directly into the cactus soil but as with all cacti, they are slow germinating and developing so patience is required to produce a mature plant which can take many years. Always make sure that you use seeds from a reputable supplier and make sure when you purchase them that they are fresh as if out of date they will not be viable and will not germinate.
Notes on cactus soil
A reputable cactus soil that is available from suppliers is designed to have excellent drainage, they will hold small amounts of water but are designed to provide drought conditions which replicates the natural habitat of cacti. Cacti do not like wet feet, they prefer an occasional water but any excess water must drain away quickly. There are many components used and these could be mixed in various ratios depending on the supplier but many common ingredients can easily be listed, many experienced growers prefer to make their own mix which works for them.
Common ingredients used include grit, pumice and sand. On a personal basis I experimented with a mix of 10% multipurpose compost, 45% vermiculite and 45% baked clay cat litter, this worked well for me but as mentioned everyone has their own way of mixing soil and a little experimentation goes a long way!