GARDENING COLUMN: Cacti and succulent season
AS we face one of the hottest weekends of the year many may say the only plants to grow in Central Queensland should be Cacti and Succulents. Yet Cacti and Succulents are some of the most highly specialised varieties of plants found on this earth. These plants have evolved to survive heat, cold or high altitudes and long droughts by being able to store moisture in the fleshy tissue of their stems, roots and leaves.
Though Cacti and Succulents have always been stereotyped as desert-only plants, they do have a wide range of habitats, from snow-clad alpine slopes and arid planes, to humid jungles. In harsh dry habitats, cacti and succulents have the ability to endure massive extremes of temperature, from freezing nights to blistering hot days. While only some can survive without water for years on end, most grow in areas which receive sporadic rainfall between droughts.
Cacti are the spiny ends of the succulent plant spectrum, and they come in a huge variety of shapes, colours and sizes. Most have remarkably large and colourful flowers, from bright red to through to white and anywhere in between, although you could wait a few months to decades for these flowers to appear. Cacti are generally easy to grow, with minimum requirements, even in our local climate.
Some of the more common varieties are the Epiphyllum or Orchid Cacti with some of the most magnificent flowers, Lobivia which has large funnel shaped flowers, Notocactus also with showy flowers, and Mammillaria with small bright flowers appearing in a ring around the top of the cactus.
Then there is my favourite and one of the most popular Cacti sold in Queensland the Golden Barrel Cactus or Echinocactus grusonii. This almost spherical ball shaped cacti can reach over 1 metre in size and live in a home garden for up to 30 years. The Golden Barrel Cactus can be found growing in volcanic rock on 1,400 metres high slopes in the east-central region of Mexico. Sadly the Golden Barrel Cactus is rare and critically endangered in its natural environment. What you may not know is that this Cactus is also known as the Mother-in-Laws Chair.
Succulents are different to Cacti but they share some common features, such as fleshy leaves or stems, are available in many intricate growing forms, in a range of colours and bear vibrant flowers, and, although they don't have spines like cacti, they may have spiny edges or leaf tips.
Some of the varieties of succulents that you are likely to encounter are Aeonium with rosettes of leaves at the end of the stems, Agave with rosettes of tough leaves with a hard spine, Aloe which is best known for the herbal uses of the Aloe Vera variety, Euphorbia which all have toxic sap such as Poinsettia, and Sedum which is a very hardy variety.
Many people would have noticed the large collection of Cacti and Succulents growing in the Brigg Street garden of Marie Fuller. This Frenchville garden is a credit to the hard work and dedication of Marie and Bernard.
Light is a very important factor in the growing of succulents, with mature cacti and succulents needing full sunlight. While they are best grown outdoors or in a sunny position such as a windowsill or greenhouse, they may require some shading from the hot summer sun in their first year, or for a few days after being moved outdoors.
Cacti and Succulents require soil or potting mixes that are nutritious, porous, and most importantly, free-draining. Depending on the growth rate of the plant, which for most is quite slow, re-potting is required to allow for root growth. Container-grown plants should be re-potted every two to three years to refresh the soil. Any re-potting is best done at the beginning of the growing season.
Water is probably the most difficult factor to get right for these plants. As a general rule, allow the soil to dry out completely between watering. This may vary from one to two times a week in summer, to one or two times a month during winter.