The mighty agaves with their fleshy, thorn-armed leaves can also often be found in German gardens, but have to be cultivated in pots due to the lack of winter hardiness. However, a few species defy cold and frost, which is why they can stay outside even in the cold season under certain conditions. The following article reveals whether and how you can spend the winter outdoors.
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Frost-tolerant agave varieties
Agaves are widespread in the arid regions from the southern United States through Central America to northern South America, with most species native to the deserts of Mexico. The impressive succulents are therefore used to a tropical to subtropical climate and are not hardy here – with a few exceptions. These come from locations where they are occasionally exposed to severe frost and have therefore been able to develop a certain insensitivity to the cold.
Some species, such as the large-thorned agave (bot. Agave inaequidens) grow in the mountainous regions of Mexico, while others, such as the mescal agave (bot. Agave parryi), are at home in deserts with sometimes considerable temperature fluctuations. Extremely high temperatures prevail here during the day, which can drop into the double-digit minus range during the night hours. Accordingly, agaves like the following are considered frost tolerant.
Agave chrysantha bis Agave montana x gracilipes
Agave chrysantha
- located in the state of Arizona in the southwest of the USA
- grows at altitudes of up to 1800 meters
- Growth height up to 100 centimeters
- Growth width up to 180 centimeters
- tolerates minus temperatures of up to minus 15 degrees Celsius
Agave havardiana
- native to the southwestern United States and Mexico
- grows at altitudes up to 2000 meters
- Growth width up to approx. 80 centimetres
- tolerates minus temperatures down to approx. minus 18 degrees Celsius
- recommended as a particularly hardy variety ‘Jeff Davis’
agave
- Giant agave from central Mexico
- grows at altitudes up to 2400 meters
- Growth width up to three meters
- tolerates minus temperatures down to approx. minus 20 degrees Celsius
Agave lechuguilla
- small agave from Mexico
- only grows to about 50 centimeters high
- forms numerous runners
- grows at altitudes of up to 2300 meters
- frost hardy to about minus 15 degrees Celsius
Agave megalacantha
- Diameter up to 100 centimeters
- one of the hardiest agaves
- tolerates minus temperatures down to approx. minus 25 degrees Celsius
Agave montana x gracilipes
- Hybrid of Agave neomexicana and Agave lechuguilla
- grows in open grassy landscapes and on rocky soils
- Growth width up to approx. 100 centimetres
- frost hardy to about minus 15 degrees Celsius
Agave neomexicana twice
New Mexican Agave
- small species from Mexico
- Subspecies of Agave parryi
- Growth width up to 80 centimeters
- tolerates minus temperatures of up to minus 25 degrees Celsius
Agave ovatifolia
- based in Mexico
- grows at altitudes of up to 1300 meters
- Growth height up to 90 centimeters, growth width up to 120 centimeters
- frost hardy to about minus ten degrees Celsius
Agave parryi
- small genus from Mexico
- thrives at altitudes of up to 2500 meters
- Frost hardy to about minus 20 degrees Celsius are two subspecies
- affects the subspecies parryi and cousii
Agave utahensis subsp. kaibabensis
- located in the Southwest of the USA (Grand Canyon Region)
- grows at altitudes up to 2000 meters
- short stature
- Growth width up to 40 centimeters, growth height up to 30 centimeters
- tolerates minus temperatures down to approx. minus 20 degrees Celsius
Agave utahensis var. nevadensis
- based in the Southwest of the United States
- grows at altitudes up to 1700 meters
- short stature
- Growth width up to 40 centimeters, growth height up to 30 centimeters
- tolerates minus temperatures down to approx. minus 15 degrees Celsius
Agave victoriae-reginae
- rare species
- native to the Chihuahuan desert of northern Mexico
- remains small with a growth width of up to approx. 80 centimetres
- pretty green leaves edged with white
- tolerates minus temperatures down to about minus ten degrees Celsius
- Fleece cover recommended for outdoor wintering
Main problem moisture
But even winter-hardy agaves like the varieties listed here have a much bigger problem in Central European winter than cold and frost: Above all, the wetness that is typical of the cold season in this country makes life difficult for the desert and steppe plants, which are perfectly adapted to drought. In their homeland, many species endure freezing temperatures by drastically reducing the water content in the leaves – plenty of glucose remains, which in turn protects the leaves from freezing. Once these are frozen stiff due to excessive water content, the cell structure is gone and only dead, muddy tissue remains. The often high level of moisture in the soil is also deadly, because waterlogging and frozen soil also ensure that first the roots and later the whole plant die off.
Overwintering agaves outside
On closer inspection, it is noticeable that agaves that are considered hardy do not necessarily perish from frost, but from the almost unavoidable winter wetness. If you want or have to overwinter your specimens outside, you should urgently protect them from moisture – this also and especially applies to snow. In addition, even very robust species do not tolerate permafrost in this respect, but are only adapted to short-term low temperatures. For these reasons, you should only plant agaves in regions with mild winters, such as wine-growing regions or along the coast. On the other hand, where the winter can be severe and snowy, it is always advisable to spend the winter in a cold store.
1. Location and soil
- dry, sandy-loamy soil with high permeability is ideal
- should hold water poorly
- create deep drainage before planting
- several centimeters thick layer of sand or gravel
- plant preferably on the upper part of a sunny slope
- Danger of waterlogging is significantly lower here
2. Cold protection
Even if some agaves are classified as hardy, you need protection against the cold if the temperatures are below zero for longer periods of time. This applies not only to specimens planted in the garden, but above all to those potted plants that can no longer be brought to the winter quarters due to their sheer size. Frost-hardy agaves in pots can be overwintered outdoors at mild temperatures as follows:
- Place the bucket as close as possible to a house wall
- Place the bucket on a thick wooden or styrofoam base
- wrap with gardener’s fleece/frost protection fleece and linen/jute
- Cover agave with sticks
Always use only air-permeable materials (no foil!) to protect against the cold, otherwise the humidity inside will increase significantly and the plant will simply rot.
3. Proper care in winter
Regardless of whether they are hardy agave or not, wintered in the cold or in the (cool) conservatory: All agave varieties must not be watered during the winter months! This is the only way for the plants to survive brief frosts. As soon as the temperatures rise again and the succulents are placed outside again after spending the winter in the cold store, you can reach for the watering can again. Also, make sure you spend the winter cool at temperatures between five and ten degrees, because only then do agaves need little water.
