Origin and appearance
Agaves (Agave) are succulent houseplants and potted plants which are characterized by very decorative, fleshy, sword-shaped leaves which emerge rosette-shaped from a base. In some species, the leaf rosette sits on a short trunk. Depending on the species, they are green or bluish-green in colour, but there are also multicoloured varieties, for example Agave americana var. medio-picta ‘Alba’, whose individual leaves each have a white stripe. The succulents are true dry artists: like the aloe and the fat hens, they store water in their fleshy leaves. In addition, the leaf surface is often covered with a waxy layer and covered with small hairs that protect it from drying out winds. For this reason agaves also survive longer dry phases well. Depending on the species, the individual leaves can be up to 150 centimetres long and 20 centimetres wide. Originally, agaves originate from the south of North America, Central America and the northern parts of South America, where they grow in deserts and semi-deserts. Certainly you have also noticed the mighty figures of free-growing agaves in the Mediterranean area, for example on the Costa Brava or on one of the Greek islands. The first specimens were introduced there after the discovery of America and gradually spread further and further.
At their natural location in Mexico and Central America, the succulents are of great economic importance. For example, the sisal agave (Agave sisalana) is an important fibre supplier and the agave syrup often used in Central European cuisine is obtained from various types of agave. Not forgetting, of course, one of the most important and productive products of the Agave: Tequila, a high-proof schnapps made exclusively from the heart of the Blue Agave (Agave tequilana).
Well over 200 species belong to the plant genus agaves. The American Agave (Agave americana) is particularly well known among gardeners, but due to its impressive size of up to three metres in diameter of the leaf rosette it is only recommended for really large tubs. It is one of the most hardy agaves in winter and can easily withstand temperatures of less than ten degrees Celsius. Even though a few Agave species like Agave megalacantha or Agave parryi are hardy in winter, most species do not survive the winter outdoors and are therefore suitable for planting in tubs or as indoor plants. Especially the small species like the thread-bearing Agave (Agave filifera) or the King’sagave (Agave victoriae-reginae) are recommended.
The Agave belongs to the asparagus family (Asparagaceae). And indeed, the flower stem, which can grow up to twelve metres high depending on the species and springs from the centre of the leaf rosette, at first glance looks a little like asparagus. Such large flower stems are mainly formed by the American Agave. However, it can take several years before the flowers bloom. So this type blooms at the nature location after 10 to 15 years, in Central Europe even only after fifty years. In the past it was assumed that the plant would only form flowers after a hundred years, so the name “Centennial Agave” has remained true to this day. For this reason the American Agave is also called “century plant”. A flowering Agave is quite rare – luckily, because many species die after flowering. When the agave then flowers, there are several flower fans on the flower stems – partly on short stems – which consist of numerous, mostly yellow individual flowers.
Because of their mostly low winter hardiness, agaves are mainly used as houseplants or pot plants. In the house they prefer a sunny place on the windowsill and also on the terrace the location should be sunny and warm. From May to October agaves can stay outside. If you live in an area with mild winters, you can also plant the hardy agaves in the garden, but then you should choose a sheltered place on a house wall or, for example, in front of a natural stone wall that gives off heat to the plant at night. Since agaves are particularly sensitive to winter wetness, a well drained soil is indispensable.
When planting agaves, the choice of the right container and substrate is the key. The succulents do not tolerate waterlogging and generally prefer a dry soil, therefore a vent hole should be provided in any case. To ensure good water drainage, you should also fill in a drainage layer of expanded clay or other coarse-grained material. Agaves are often cultivated in nurseries in normal potting soil. In order for them to thrive well, however, they need a substrate for succulents, since their requirements are very similar to those of cacti. The ideal substrate is highly permeable to water, low in nutrients and interspersed with mineral components such as lava granulate or quartz sand.
Agaves do not have to be cut. For optical reasons, however, dead leaves are removed by cutting them off with a sharp knife at the bottom of the rosette. Since one can seriously injure oneself at the prickly leaf-tips of some types, some hobby gardeners cut these off regularly with the garden-shears.
Winter protection and overwintering
Most agaves are not hardy and must therefore be wintered in a bright place in the house or greenhouse. When the plants have to be cleared into the house depends on the species. Here you should inform yourself beforehand about the winter hardiness of the respective Agave, because some species tolerate frost at short notice, others however not at all. To be on the safe side, however, we generally recommend a frost-free wintering area. The optimum temperature here is between 10 and 15 degrees Celsius. The plant does not need to be fertilized in winter and you should also be economical when watering it. However, the bale must never dry completely. The warmer and sunnier the agave is during the winter, the higher its water requirement will be, of course, and when it gets warmer in late spring, agave can move back outdoors. However, the pots should first be placed in semi-shade for a few days in order to slowly get the plants used to the higher temperatures again. Planted out agaves need some additional protection, especially in the first years after planting, for example by fir twigs or a fleece. In order to avoid winter wetness, a roofing is also recommended.
Further care tips
Since agaves originally occur in deserts and semi-deserts, they should only be cast very moderately. It is better to have too little water than too much, because the succulents react sensitively to waterlogging. The plants also need water in the winter quarters, but only so much that the bale never dries completely. Rainwater is best used for watering, but agaves can also cope with tap water containing lime. In summer they should be fertilized with water every 14 days. A succulent fertilizer, for example, is suitable for this purpose. In contrast to many other indoor plants, agaves tolerate very dry air, so additional humidification is not necessary. The succulents should be repotted about every three years. For this work you should wear gloves, because the spikes at the tips of the leaves are very tough!
As a rule, agaves are propagated via so-called Kindel, since propagation via seeds is very time-consuming because of the rare flowering. However, all agave species form childel, i.e. offshoots or secondary shoots. If these are allowed to grow further and not removed, they become larger and larger over time and eventually displace the mother plant. The children and their roots are either carefully excavated or removed with a knife or scissors. Then you plant them in cactus soil and place them in a warm, bright place, but not in the blazing sun. As with adult specimens, watering the offspring is only moderate.
Diseases and pests
Agaves are very robust and are rarely attacked by diseases and pests. If the lower leaves turn yellow or wrinkly after repotting, this is a sign that the plant has not grown properly or that the substrate is not optimal. Then you should repot your Agave as soon as possible. If the agave is too wet, root rot may occur.
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.