Succulents and Cacti at Altitude

By Jan Boone

Many of us have a quiet sunny corner in a room where favorite winter houseguests have camped out for the past 5 months or so.  These are the best kind of guests because all they require is sun, occasional water and loving words as we pass by.  As much as we enjoy their presence in that sunny corner, it’s getting time to consider who can maybe return to outside decks, who needs a new container and who is tolerant enough to be planted outside in the sun.  Succulents provide diversity in colors, shapes and textures in our gardens and decks.

                                                

Photo by Jan Boone

Whether inside or outside, start with the premise that for the most part succulents & cacti demand attention to 3 fundamental basics in order to survive our high, cold and dry growing zones. These include light (depending upon varieties, at least 4 hours of direct sun and afternoon shade); soil to promote drainage since soggy roots simply produce root rot or fungus; and lastly, water.  While many cultivars are drought resistant perennials, it’s important to know plant water needs may require a more selective approach, especially when planting adjacent to one another. Watch to see what your plants tolerate. Succulents store their water in their fleshy leaves or stems and we all know when the temperature drops, those leaves may freeze and the plant is damaged or killed.  

A fourth area of consideration is the more common type of insect infestations you may discover before you start shifting containers or planting for the summer season.  These can include mealy bugs, whitefly, scale, aphids and some mites.  Inspect your plants closely.

Whether in smaller terrariums or larger outside settings, cacti are most selective about their clay soils, good drainage and limited watering needs.  Ball and barrel shapes may add diversity to your decks or rock gardens but winter protection is essential so containerizing these may be a safe bet. 

Perhaps you’ve hosted some of these visitors during winter months:

Jade plant Crassula ovata. Mine is a cutting from my mother’s immense container plant that lived on a balcony in direct afternoon sun in California for years.  Originally part of a diverse plant genus from Africa, the Jade plant has undergone a variety of scientific classification name changes.  This is a popular indoor only houseplant that can thrive on neglect!  My only issue is susceptibility to mealy bug.  At least once a year I find myself gently cleaning leaves w/q-tips, alcohol and soapy water.  These varieties are popular in small terrarium size plants or as large container plants. It does bloom, but more frequently in larger mass plantings. They will not overwinter outside at our altitude but may be content with an occasional secluded warm afternoon on an outside deck. Water is stored in the leaves, stem and roots.  Roots can do well in compact container settings.

Aloe pup 

Aloe Vera Aloe barbadensis.  Aloe is a good specimen to have in a container for the dramatic leaves as well as for its medicinal qualities.  Break a leaf spike off and you’ll find a gel good for burns and minor cuts.  Because I ignored this plant for quite a while, other than occasional watering, I learned what plant pups are!  Like many succulents, this plant reproduces by growing ‘pups’ from a main root. (Also referred to as offsets, or root portions that develop leaves and sprout a new plant).  Break pups off carefully, soak for 24 hours prior to re-potting and you have a new plant.           

Hens and Chicks Easily one of the most popular of so many colorful and unique Sempervivums.  Check the cultivar for hardiness.  Good in containers as well as planted in the right site.

Snake Plant Sansevierratrifasciata Popular as the Snake Plant or Mother-In-Law’s tongue among interior plant circles, but it is actual a succulent from Africa and Madagascar.  It’s low-light and easy maintenance needs are alluring.  Caution … this is a plant not meant for outdoor containers or use.  It’s perfect for an indoor succulent specimen.

Sansevierra pup

Pencil Cactus Euphorbiaceae tirucalli This is one of the first and more unique succulents I learned about upon moving to Colorado.  It is not an actual cactus despite the name, but a true succulent.  It is part of the Euphorbia family.  Members of this family can be annual, perennial, evergreen, shrub-like in gardens or even tree-like.  My initial encounter was a unique 5’ tall interior specimen.  Years later, I still like the vertical, simple nature of the plant and have a 6” high specimen in a terrarium bowl.   A characteristic this family all shares is the milky white sap that can irritate or be toxic to people and animals.  If you’re taking cuttings for propagation, wear gloves and don’t go near your eyes while handling anything w/sap.  There are more varieties that can be planted in outside beds in warmer zones, but not for our cold.  Keep in mind this family includes spurge varieties and even poinsettias!

Pencil cactus container growth

Stone succulent

Stone Plant Lithops marmorata I’ve always thought these small, funny ‘living stone’ succulents looked intriguing.  I became more interested by these as I’d pass large trays of 2” pots for sale at box store garden centers. From South Africa originally, they grow to mimic the rocks and dry environment they grow among. They will test the most determined grower!  Sometimes they split, sometimes they bloom and sometimes they just die!  I’ve discovered The Denver Botanic Gardens has a bed of them in their Steppes gardens to promote education about the threatened Steppes regions around the world.  The stems and roots are underground, while large rounded   leaves store water.  These are highly sensitive to cold and water, so require protection in winter months the payoff is the interesting addition to a xeric or rock garden space in your yard.  Leave them alone and they’re happy when dry and warm.

These are just a few of my winter houseguests, but as I pass through garden centers now, I think perhaps I need to add a few new varieties to my deck containers this coming season.  A great reference tool for anyone interested in succulents or cacti  is Hardy Succulents by Gwen Moore Kelaidis, Storey Publishing, 2005. Currently it seems everyone is selling containers filled with multi-colored varying succulents, so it’s good to know what can work for your own house and garden environment.  Enjoy the fun!