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Cordyline problems – pests, diseases and other problems
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Cordyline, sometimes referred to as cabbage palms, is a plant native to south-eastern Asia and Australia but one that grows just as well throughout the UK depending on the variety. Depending on the age it can span between 3 and 10 meters in height but you usually see taller ones further down south where the winter is usually milder. Cordylines prefers full sun but will thrive well in light shade. There is one variety that is particularly hardy that can be used outdoors in the UK, Cordyline Australis, it will tolerate temperatures of -5 degrees if it’s planted in a sheltered region. If you have any other variety beyond this one you will have to protect it in the winter and take extra steps to prevent pests and diseases by maintaining an environment with temperatures around 15 degrees Celsius. Most of the Cordyline Australis plants will survive over winter so long as they are sheltered. If you have a different variety you will have to take steps to move it indoors or put it in a greenhouse to give it extra protection against disease often brought about my winter conditions.
Otherwise, these plants are incredibly easy to grow and they simply need fertile, well-drained soil which is truly the key to preventing a great many diseases. With a well-balanced fertilizer and a keen eye toward pests, you can keep your cordyline healthy for years.
There are two types of pests that might affect your cordylines. The first is spider mites which is more common in varieties grown indoors or in a greenhouse. Spider mites are almost impossible to see with the naked eye if you aren’t looking for them specifically, they are so small. Most people notice the webs before they notice the actual spider mites. These are tiny insects that suck your plant sap directly out of the leaves which distorts them. you can knock them off your plants by spraying them with water but this should be done in the early morning so that the leaves have the opportunity to dry out before the weather gets cooler.
You can also circumvent the issue entirely by letting loose ladybugs on a regular basis during the growing season as ladybugs are natural predators to aphids and spider mites alike.
If the issue is particularly problematic you can invest in a pesticide spray to do away with the spider mites.
Of similar concern are thrips. These are also sap-sucking insects as well which will discolour and scar your leaves but can also stunt the growth of your entire cordyline plant. If you see an infestation of them you should cut away any affected part of the plant and destroy it immediately, after which you should sterilize the tools you use to do that. Spray the remaining plant with insecticidal soap. Again, you can also release things like ladybugs or lacewings both of which will eat the population and help manage it.
Where to buy Lacewings and ladybirds
You can actually buy them as larvae online and have them delivered to your door, they are actually known as a biological control as apposed to spraying chemicals.
Common Cordyline Problems
Leaves turning brown at tips
With this particular plant you have to be careful if your water has extra fluoride in it. It is for this reason that any container-grown cordyline plants are to be watered with distilled water. If you notice that the leaves are turning brown at all of the tips it’s indicative of fluoride toxicity. If you use tap water when watering your plant and the water is heavy with fluoride the tips of your leaves will start to turn brown and eventually all of your leaves will become mottled and die. If possible use rain water or distilled water.
Leaves turning yellow and brown and drooping
If the leaves are turning yellow and brown and drooping, by comparison, this is simply indicating that the plant needs regular, deep watering. The key here is to keep the soil regularly moist but never over water the soil. With container-grown plants which are how many gardeners grow cordylines, you can water them until such time as you see that water coming out of the drainage holes and then you want to leave the pot until it is almost dry before you water again.
Leaf Spot disease
There are a few diseases that you need to look out for with cordyline plants. The first is leaf spot. This is a fungal disease that will discolour your leaves. The best way to prevent this is to water the roots of your plant. Most people water the stem or the leaves mistakenly which leaves extra water on the leaves and in colder weather this provides the perfect environment for fungus to thrive.
Preventing leaf spot
It’s also recommended that you water early in the day so that if any water does splash onto the leaves or the stem it has an opportunity to dry out before the evening temperatures drop. It’s always good to check the air circulation around your plants as well as any insufficient air circulation will create a habitat perfect for leaf spot.
Dealing with leaf spot on infected plants
If you notice your plant is affected, remove any of the affected branches and destroy them. Any tools you use for this process should be disinfected. If your plant is severely affected by leaf spot you might need to turn to a fungicide which you can get from most garden centres and nurseries.
Fusarium pathogen causes root rot, another concern associated with cordyline plants. This type of rot is caused by poor drainage or excess watering. It is for this reason that you absolutely must allow your plant to dry out so early in between waterings so that the roots never sit in waterlogged soil.
Protecting cordylines from cold weather
If you see your plant has yellow and brown patches at the early spring on its leaves and some of those leaves have dropped off, your cordyline plant was likely damaged by winter weather. After a particularly severe winter, your plant will come away looking quite battered especially if your area was subject to strong wind or cold snaps. It is best to always protect your plant against winter weather by tying it up pulling the leaves together and covering it with fleece, this will help protect the crown. When the weather improves the plant will naturally perk up an any legitimately damage gross can be removed.
Cordyline slime flux
Cordyline slime flux is a particularly nasty outcome of insufficient protection against winter weather. This is a disease caused by bacteria. The bacteria are only able to get into your cordyline plant once it has been damaged by Frost. If you live in an area with particularly cold weather, should water remain in the stems, leaves, or the roots the remaining water can actually freeze and cause tissue damage from the inside out. Any areas that are so damaged become a gateway for bacteria.
Once the plant is affected by this bacteria you will notice a thick, white fluid on the stem. It might have a particularly foul smell. If not white, there could be black stains directly below the white fluid. If you see any of this, it’s imperative that you cut away the affected stems and destroy it along with any other damaged tissue you can find. Only by destroying the damaged tissue and removing it can you prevent it from spreading.
Preventing slime flux
The best line of defence against this bacteria is to protect your plants against winter weather. If you have containers or pots, bring them into a greenhouse or inside your home. If that’s not feasible, cover the pot with bubble wrap to protect the roots and tie the rest of the plant up with string and wrapped with fleece to protect it. If your cordyline is in the ground and you simply can’t move it, wrap it and mulch the ground around the base of the plant.
Overall the best ways to protect your cordyline plants are to be completely cognizant of when you water and where you water and then to provide proper protection in the winter. By watering at correct intervals, allowing the plant to nearly dry out in-between time and watering at the roots rather than along the leaves, you can prevent many of these diseases and common problems listed above. Protecting your plant over winter will go a long way towards sustaining its overall well-being.