As spring starts heating up your Cymbidium blooms will slowly start fading and finish flowering. At the nursery we get a lot of questions from gardeners on why their Cymbidiums haven’t flowered this year or even for a few seasons in a row. The reasons for them not flowering are often one or a combination of the following: insufficient feeding, that they are kept in the wrong spot or that they need repotting or division.
To understand the repotting we have to first understand a few orchid terms. Cymbidiums grow by means of a bulbous structure called a pseudo bulb which in essence acts as a storage mechanism for water and nutrients. If a bulb has flowered once it won’t flower from that same bulb again. In time the bulb slowly loses its leaves and dies off, all the time giving its energy back to the growing bulbs. These bulbs are all connected by an underground rhizome which has a distinct direction of growth. Problems arise when there is no space for the new pseudo bulbs to grow this is why they need repotting every few seasons.
Before you start repotting make sure that you have all the necessary tools. You will need a sharp sterilised knife, a pair of scissors and a suitable table or flat surface to work on. It is very important to sterilize your tools especially when working with multiple plants, keep a spray bottle of diluted methylated spirits nearby and give you’re tools a spray and wipe down every now and again.
Start by removing the plant from its old container by gripping the plant tightly and pulling it out slowly from the pot. Root bound plants can removed by turning the pot on a surface and tapping the sides as you turn to loosen the roots. Remove the old potting medium by shaking it off or by placing it under a tap and washing out the old mix.
At this stage I prefer to clean the plant up a bit. Remove any dead leaves, old stems and any weeds that have made a home in your orchid. This will make the rest of the repotting easier as the plant is not as cluttered with dead foliage. If the roots are very overgrown or if the plant is root bound I would recommend trimming them back slightly.
The next step is to prepare your potting mix. Here at the nursery we use a mix of 1 part potting soil to three parts bark. Cymbidiums generally prefer bigger pieces of bark, we find 50mm bark chips are the ideal size. There are so many different mixes one could use with great results. Ranging from coconut chunks to chopped up palm fronds, just make sure that your mix drains adequately and doesn’t break down too quickly. If you want you can even mix in an organic fertilizer such as Bounce Back to give them that extra boost.
Now you have to decide if your plant needs just repotting or if it needs to be divided, this all depends on how many actively growing pseudo bulbs the plant has. Divide the plant if it is overcrowded or if distinct groupings of bulbs have formed. When dividing it is best to try and keep at least a minimum of 3 bulbs together as the more actively growing bulbs the plant has, the better its chances will be of flowering the next year. Cut through the rhizome applying even pressure without damaging any of the nearby bulbs. Always be careful when dividing that you don’t damage the young bulbs that are developing as they can easily break off. Ensure that your group of bulbs has enough roots to sustain it.
Time to start potting them up in your fresh orchid mix. When repotting Cymbidiums don’t use too big a pot, we find that a 23 cm pot is the ideal size as they are a lot easier to work with and move around and funnily enough Cymbidiums tend to flower better and more profusely in a smaller pot. If you want you can add gravel at the base of the pot to improve drainage and add weight to the pot. Hold your grouping of bulbs in its position to be, allowing space for the new bulbs depending on the rhizome’s direction of growth. Fill up with your potting mix trying to work it in between the roots till the bottom third of the bulbs are covered. Water them thoroughly afterwards to get the mix settled and the roots growing, thereafter water and feed as per usual.
There you’ve done it, give your self a pat on the back and admire your happy cymbidiums in their new home, now you can start looking forward to the masses of blooms you can expect next year.