Larry Smith and the Riverside Gardens team talk all things pots, plants and pruning in their weekly gardening column.
Well, I hope you and your garden managed to get through the extremely windy weather earlier this week; it certainly has caused widespread damage across the state. I was lucky enough or unfortunate enough, depending on how you look at it, to be out in the middle of Bass Strait on King Island last weekend, and I have never seen three days like it. The wind peaked at 158km/h, and it blew for the whole time we were there.
The amazing thing, though, was the way the coastal flora stood up to the constant barrage of the wind. The Melaleuca, Leptospermum and, a little further inland, the Banksias just bent with the wind and allowed it to pass through them using their combined mass to support each other against such an awesome force.
There was some damage but nothing like what you would expect on such a front-line planting. It just goes to show how important plant selection is and what an amazing landscape gardener Mother Nature is. It also highlights how things work together in the environment and how we need to look after that delicate balance.
Having cleaned up around the nursery and gardens after the winds, we have resumed our spring potting up of all the bare-rooted stock. This ends the bare-rooted season for this year, but although it has been very popular, as the plants break their dormancy, they must be potted so they can continue to grow through the coming months. This includes all the roses, deciduous fruit trees and deciduous ornamental trees. So if we have the numbers right, we will have plenty of this beautiful stock to sell in the coming months.
It is the ideal time for you to be doing your own potting up around your garden. Those empty pots can be filled up with flowering seedlings to add a splash of colour to your alfresco area or summer herbs and vegetables for easy picking near the kitchen. Long-term potted plants can be moved on to the next-size pots or knocked out of their existing pots, and their roots can be trimmed and re-potted with some fresh new potting mix.
Most plants will respond well to re-potting in spring, but plants that are just coming into flower, like Azaleas, Camellias or Boronias, are best left until they have finished their displays before disturbing their root systems. For most plants, re-potting or potting up is very simple, but there are a few points that you should keep in mind.
Number one is to use a good quality potting mix. You will be amazed at the different results you will get with the different quality of mixes. The amount of fertiliser you have to use to get any plant growth, the amount of water they do or don’t retain, and the length of time they hold up before they lose their structure and collapse, all vary with the quality of the mix. This will result in poor growth or plant loss and a waste of fertiliser, time, effort and money.
For long-term potted plants, use the best-quality mix you can find. You will pay a bit more, but you will get the results and not have to redo it all in six months. For short term plants like flowering annuals, vegetables and herbs you can get away with using a slightly lesser quality premium mix.
Do not add soil, compost, manure, sand or gravel to your potting mix. This will destroy the balance of fine and course particles that make up structure and airspace of the potting mix, which is critical for good growth.
Choose a pot size that is suitable for the purpose; the finished product should look proportional and balanced. The pot should be big enough for the plant to grow into the size you want, but not overly big so that the roots take forever to reach the wall of the pot. Over-potting will give you a much slower growth rate.
When potting, you do not have to destroy the existing root ball, but it is a good idea to loosen the roots at the bottom of the plant, particularly around the old drainage points of the pot they came out of. Half-fill the new pot with potting mix and place the plant in the centre of the pot. Make sure the top surface of the root ball is at least 2cm below the top of the pot rim, then fill in around the roots, gently compacting it as you go. Once backfilled completely, water the plant with a good soak; at this stage, it is not a bad idea to add plant starter to the water to help them re-establish their root system.
Finally, give the plant a light trim over and a feed with a slow-release fertiliser, then sit back and marvel at your workmanship as it grows into a beautiful feature in your outdoor space.