Succulents: Survivors of the Winter

Aloe spp.

When planning for hot and dry condition planting, succulents are often among the top candidates because of their ability to withstand prolonged periods of drought.  On the other when it comes to planning for winter interests, seldom do they ever get recommended.  This could be because of an unspoken assumption that when a plant is heat tolerant, it does not like the cold.  This assumption is not valid.  Like all gardeners who have grown some of them, I can say that with the appropriate variety and suitable location in the garden, succulents can be among the few interesting plants in the dead of the winter.  While the rest of the traditional plants go into dormancy, some succulents continue to grow changing their colors in response to the temperature and light intensity.

Echeveria 'Neon Breakers' (Fall)

Echeveria 'Neon Breakers'  (Winter)

Succulents cover a wide range of plant species that originated from places of varied climes.  Some have come from the tropics (rain might be prevalent but some succulents grow on trees where the roots cannot reach the ground); arid regions (deserts have low rainfall and high temperatures that limit water supply); coastal areas (water may be available but it is usually loaded with high levels of salts and minerals - beyond the threshold levels for most plants); and the alps (precipitation may come fresh in relatively larger quantities but it is frozen and unavailable for plant consumption).  With that in mind, it is not surprising that some succulents respond differently under varied  environmental conditions. And that is why, some succulents can be winter gems even in temperate areas.

Aeonium 'Kiwi'

      Sedum rubrotinctum 'Pork and Beans'

Succulents is the collective term for drought-tolerant plants with the characteristic thickened fleshy organs (leaves, stems, or roots).  Whether the plants evolved (over the years) to come up with this type of specialized fleshy tissues as survival mechanism or whether they were originally endowed with such characteristics the first time they sprouted in the Garden of Eden, I am not sure.  However, if such character traits of succulents allow them to survive the extreme dry conditions, how much more would they favor the plants that are grown in gardens where almost everything is manipulated to provide favorable conditions for the plants?

Wooly Rose (Echeveria cristata 'Doris Taylor')

California is known for its generally mild climates but my garden - being in the foothills of the Sierras - experiences both ends of the thermal spectrum.   We have very hot summers and freezing winters.  Over the years I have observed that only few of the succulents in my collection are susceptible to the cold.  In fact most of them are very resilient and they display very interesting colors during the colder months.


Aeoniums, Sempervivums, Aloes, and Sedums are among the ones that consistently do well in my garden.  Others like Echeveria also do well depending on variety and microclimate. The earlier they get the morning sun, the better - as this would shorten their exposure to freezing temperatures.  Although succulents prefer some amount of shade in the summer, plants that are placed on the south-facing side of the garden have a better chance of withstanding the harsh winter nights.

   

With the right variety and microclimate, succulents can be the garden gem that sparkles in the winter.

Suitable or Questionable?

Wooly Rose (Echeveria cristata 'Doris Taylor') cannot withstand freezing temperatures.

Questionable Plant.  Some of my frost-sensitive plants get special treatment these days by being placed close to the house to take advantage of the heat from the walls.  They are also moved around where they can be in the sun even for just a few minutes of the day.  Frost damage can be avoided or reduced when the plants get a chance to recover by getting exposed to warmer temperatures early the next day.   This wooly rose (Echeveria cristata) cannot withstand freezing temperatures - a lesson I learned last year.  Fortunately, it survived and that is why it is still here - but it is now under observation.  Plants that die in my garden because they require too much care do not deserve to be here.  

Suitable plants are beautiful.

Suitable Plant.  If a plant proves to be suitable under our climatic conditions and if they prove to be beautiful and requiring minimal maintenance, then it deserves consideration.  It is guaranteed that it will be provided with the chance to proliferate.  

Suitable plants are adaptable.

Sometimes we fall in love with a particular plant that we ignore the amount of effort that we put into its maintenance.  As gardeners we all need to train our heart and mind to agree. 

Color Change in Citrus

Fruits on pot-grown oranges (Citrus sinensis)

Tropical Zone.  Citrus fruits like oranges and lemons start out green and remain in that color till maturity.  I remember, having grown up in the tropics, that all the citrus fruits I've seen were green.  When they are mature and harvested their color are still green different only from their immature counterparts by the shine and gloss on the rind.  By the time they turn orange or yellow, they are already over-ripe and cottony and tasteless.  Commercially grown citrus can be treated with ethylene after harvest to induce uniform and timely yellowing for a more appealing look. 

Temperate Zone.  Citrus plants grown in temperate places with mediterrenian-like climate, low temperatures induce a change in color to deep orange or yellow even before the fruits mature.   The color can be deceptive.  It is important to harvest the fruits when they are fully mature, it is when the sugar and the acidity balance is at its best. 

Lemon (Citrus limonia)

Hidden from our eyes are processes that are constantly happening in the plants.  Shifts in these processes are caused by a number of environmental factors.  The green color in unripe citrus plants is a result of the dominant presence of chlorophyll on the rinds.  The yellow or orange color in ripe citrus fruits is a manifestation of the high concentration of carotenoids.  When temperatures go down to a certain critical level, such as in the winter, the rate of chlorophyll production in the plant slows down or completely stops.     Furthermore, the existing chlorophyll undergoes a process of degradation while the biosynthesis of carotenoids increases, particularly in the fruits.

Stroll in your garden... its good for you and your plants.

Caged Plants

At this time of year, gardening is at the bottom of my to-do-list.   It is cold outside.  Other than shedding leaves, the plants are not doing anything visible that would inspire me to go work outside.  The truth is the plants are alive.  Just like any other form of life plants, even when they are not actively growing, are physiologically active.  If the needs of these living forms are neglected they will show it but usually, it will be too late.  The damage will already have been done.

Water. The one thing that I need to remind myself is to water my potted plants on a regular basis.  The roots of the plants are limited within the soil in the pot and when that soil is dry they have no other source.  Plants grown in the ground can grow their roots further just to reach the source of moisture but plants in pots are like animals in cages.  Everything they need has to be provided.   Water also helps the plants withstand freezing temperatures.

Shelter.  Plants that are sensitive to freezing temperatures need protection during the winter months.  Plants in pots are easier to move around than their in-ground counterparts.  Move them closer to the buildings or position them in such a way that they will get exposed to the southern sun.  The days are very short, it is important to allow the plants to get as much sunlight as possible.

Stroll in your garden...it's good for you and your plants.