By Mary Townsley, Mobile County Master Gardener, www.mobilecountymastergardeners.org
Succulent … juicy, right? When referring to food, yes, juicy and tasty! However, there are thousands of succulent plants, including cacti, agaves, aloes, mangaves (crosses of manfredas and agaves), sedums, yuccas, and others. Juicy, yes, but not tasty (unless you are making tequila … but that's another story).
You may think of succulents as potted houseplants. What you may not appreciate is that succulents can be used in our outdoor gardens. Yes, in our zone 8 climate with sometimes cold winter weather and certainly humid, rainy, and hot summers.
Driving around Mobile County, it's not uncommon to see century plants, Agave americana, planted in the ground along a fence line behind a drainage ditch. These agaves are long lived and can withstand temperatures down to ~15 degrees. The shape of these large plants is indeed dramatic (https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/century-plant.html).
I am particularly drawn to the leaf imprinting patterns in large agave such as these. Century plants are "monocarpic," meaning they bloom once at the end of their life (i.e., after 8-30 years). Many agaves, including the century plant, while monocarpic, are prolific producers of "pups,” offsets of the parent plant that live on when the parent plant dies.
But your choices are much broader than this. You can select from succulents that flower annually (or not), those that offset (or not), those with strappy or fleshy leaves, those that have small rosette forms or are tall specimens, and those with varying leaf and flower color.
Regardless of your choices, providing good drainage and appropriate sun exposure are keys to success with succulents in our climate. Succulent plants have specialized ways of storing water: in stems (cacti do this), in leaves (agaves and aloes do this), or in stems and roots (ponytail palms do this). This makes sense as most succulents are native to arid regions of the world, so water storage is an important adaptation which allows these plants to thrive in the face of limited rainfall. While they may need some supplemental water, their roots and/or leaves will rot in persistent wet conditions. Some succulents such as agave are quite happy in full sun, while others appreciate some afternoon shade or even tolerate full shade.
Given our typically high annual rainfall, succulents will not fare well planted in the ground here unless drainage is quite good. In-ground plantings of frost-tolerant succulents can work on a slope, on a raised berm in the landscape or in a raised planting bed. Amending the soil to incorporate a lot of inorganic matter such as gravel and/or sand will help improve drainage.
Alternatively, you can develop a succulent pot garden to provide structural interest and varied color. There are several advantages to this strategy: the smallest succulents, in fact, may be better highlighted in a pot, pots can corral offsetting pups until you are ready to transplant them, pots are much easier to cover or move into a protected area if that rare hard freeze is coming, and finally, pots allow you to control soil composition and watering. A well-draining potting mix for succulents should include 50-75% inorganic matter in the form of perlite, coarse sand, pumice, or even fine gravel such as granite chicken grit. For the organic part use coir, compost, or potting soil. Sometimes, I will add ground pine bark. Don't include materials that retain water such as vermiculite, and make sure your pots have drainage holes.
When rainfall is scarce, but your succulents are actively growing, i.e., not dormant, you will need to provide supplemental water. So, how to know when succulents are dormant? Some succulents such as haworthias, kalanchoes, and sansevierias exhibit summer dormancy. Eschevaria, euphorbias, and pachypodium are winter dormant succulents. A more detailed list of dormancy patterns can be found at https://southcoastcss.org/dormancy/.
Note that while some species of agave and aloe are summer dormant, some are winter dormant, and curiously, some do not appear to go dormant at all. Plant labels may not include this information, so do some research and watch the plant for new growth. Provide water accordingly and enjoy!
To learn more about outdoor succulents for our climate, start with one of these useful resources:
Now I am more interested in these plants.