General Information about Cordylines

Many Cordylines come from Hawaii but there are also species native to South America, New Zealand, parts of Asia, New Guinea, the islands of the Pacific, Mauritius and eight species native to Australia.  Cordylines come in many colours or combination of colours including many shades of greens, reds, pinks, purples, yellows, oranges, cream and white.  The Australian species are mostly green but occasionally variegated forms are found, these are highly prized by collectors.  Cordylines have a large range of leaf shapes and sizes with some varieties, with foliage up to a meter long with proportionate width.  Some have compact leaves of only a few centimeters in length while others have narrow strap like foliage.  

Whilst Cordylines grow in the tropics and are certainly beautiful, they are definitely not tender.  They’re as tough as the proverbial “ old leather boot laces”, growing happily in the tropics and sub-tropics down to New South Wales, provided they are protected from direct frosts.  The cold loving New Zealand species, (australis) will grow in the cooler parts of Australia.  Cordylines are at home in the garden, some even prefer almost full sun to show their best colours.  Most prefer good light with protection from the direct sun, under the canopy of palms or trees is perfect.  While Cordylines like regular watering for optimum growth, once established they will tolerate dry spells better than most plants.  In the Pacific islands Cordylines are grown right up to the beaches, standing up to the winds roaring in from the ocean, yet they look magnificent. 

Cordylines are easy to propagate.  In the warmer months of the year the plants can be lopped, place the tops in a container of water or plant in a pot containing a mixture of peat moss and sharp sand or a good potting mix.  You’ll soon have a new plant and the old plant will soon regenerate new growth.  They can also be grown from root cuttings and seed. 

Cordylines respond well to a slow release fertilizer.  Occasional feedings with soluble fertilizers is also beneficial.  Addition of extra sulphate of potash enhances their colour.  The larger majority of Cordylines dislike wet feet.  The Australian species Cordyline ‘Manners-suttoniae’ grows naturally in poorly drained situations so would be suitable for the wet spot in your garden.  

Pests and diseases – grasshoppers can be controlled by spraying with carbaryl or malathion.  Snails and slugs can be kept at bay by placing a border of sawdust (hardwood) around the garden edges or around individual plants.  When using sawdust extra fertilizing with a nitrogenous fertilizer is beneficial. 


Growing Cordylines 

There is no universal potting mix that you can put your Cordyline into and stand back and let them grow without any more attention.  There is however mixes that will let most plants do well with only a little attention. 

The important aspects of a mix are as follows: 

(1)    Holds Moisture - The mix needs to hold moisture so it doesn’t need to be watered 2-3 times a day.  Sand holds almost no moisture but clay and silt hold too much.  Pots in the full sun dry out faster than the same mix in the shade.  N.B. Same mix but a different location.

(2)    Drains Well - Plant roots use oxygen and produce carbon dioxide so they need the mix to let gas exchange occur.  A deeper or longer pot requires better drainage than a small or shallow pot due to the smaller surface area of the mix.

(3)    Holds Nutrients - An extremely open mix e.g. large bark and sand will not hold water or nutrients, so it needs smaller pieces, especially organic mulch such as compost sawdust, fine pine bark or peat, as these hold nutrients and can exchange them with plant roots.  Soluble fertilizer is largely leached out from the mix by watering because it’s soluble in water.  Fertilize with slow release granules such as Osmocote or Nutricote, release a little fertilizer each day.  Note: In your climate, the release rate may be a little faster than stated, e.g. 6 months is only about 4 ½ to 5 months.

(4)    Wets Easily - Any organic based mix when it dries out is hard to re-wet.  The mix shrinks and lets the water run down between the mix and the sides of the pot but appears wet.  Check by pushing your finger into the mix.  Very dry mixes can be re-wet by putting into a bucket of water until the air stops bubbling out.  The use of a wetting agent also helps to re-wet the mix.

(5)    Has a PH of 6-6.5 - In this range, all major and trace elements are fully or largely available to plants.  Outside this range the availability reduces, even though the nutrients are still present. 

The brief description above shows that the mix for you is partly dependant on the mix itself and partly on how and where you use it.  A good mix has some fine and course material and includes 30-50% of organic matter.