I have spent a lot of time in Cape Town recently collecting plants for the new Botanic Garden in Singapore called Gardens by the Bay and I am shocked by the devastation the drought has taken on the nursery business and on gardens in general. Unless you have a bore hole of access to water you are not allowed to water your garden which is a tragedy as many people have spent a lot of time, energy and finance creating these gardens. We know what that was like as last year we went through the same problem. Luckily the drought has broken in Natal and many of our Dams are either over flowing or filling quickly.
Buying plants is a very expensive business especially if you are looking for that rare and unusual plant. Why not find that plant in the wild or in a private garden and either collect the seed or take a cutting. I remember when I was Curator of Durban Botanic Garden I often used to hear noises coming from the flower beds ( and not what you are thinking) to find someone with a pair of secateurs taking a cutting of a rare plant in the gardens. When approached there argument was that they were rate payers so why can’t they take a cutting. Not that I am saying you must go into private gardens and take seed or cuttings of plants without permission. Even in the wild be careful when collecting seed or cuttings as you could get into hot water from the local authorities. In this article I will give you a few tips on how to grow your own plants through propagation. I will also discuss in this article how to plant trees and shrubs to get the best results.
There are many ways to grow plants. The 2 main ways are:
- sexual which is by collecting seed which is sown in a seedling tray or directly into the ground
- Asexual which is by either taking cuttings from different parts of the plant or by splitting and dividing the plant.
Sexual propagation: This is probably the easiest way to grow plants in mass. Take a plant like Agapanthus which flowers in December. Once it has finished flowering it would have been pollinated by bees or other insects that hover around the flowers collecting pollen. These old flowers will then produce a seed pod with thousands of seeds in each pod. When mature these pods will split and the seeds either dispersed by the wind or by other insects. These seeds are very light and black in color that easily dispersed by the wind. That is why bees are so important as they are responsible for probably 95% of all pollination that takes place either in nature or in the farming community. Remove bees from nature and we will starve within 6 months. Collect these seeds in a plastic packet and take them home. Go to a nursery and buy a plastic seedling tray and fill this tray with seedling or potting soil. Then place the seed in the palm of your hand and slow tap your hand that disperses the seed evenly over the soil surface. Then take some seedling mix or potting soil and evenly spread this soil over the seeds in the tray. Make sure you don’t spread it too thickly over the seed as this could prevent it from germinating. Take a watering can with a fine nozzle and gentle water the tray. Do not over water as the seed will wash out of the tray. Take the tray and place in a bright area with some direct sunlight during the day. Keep the soil moist but not over watered until you see the seedling pushing through the soil layer. Wait until they are big enough before removing them from the tray and planning in the ground. It is as easy as that. Well not really as some seeds require hot water treatment and some seeds require the surface of the seeds to be scarified but in general most plants are easy to grow and sow from seed.
Asexual propagation: this is when playing with plants becomes fun as there are so many ways to produce new plants through this means. Soft or hard wood cuttings, divisions, air layering and trungeons are just a few of the ways to produce new plants from this form of propagation. It becomes more complicated when you have such plants as bulbs that produce bulblets which are new growths that are produces after the bulb has flowered which need to be removed at a certain time of a year. Some plants also need a dry period during dormancy like tuberous Begonias which need to be lifted, placed in a dark room and left for many months. Rather complicated but that is why gardening is soooooo much fun. Maybe I need to run a workshop to demonstrate how to grow and propagate these unusual plants. Let’s take a soft grow plant such as Coleus. The best way to grow this plant is from a soft tip cutting. If you look at the plant you will have the leaves and the soft stem. Down the stem you will see divisions or knobs called nodes and between these nodes you get inter nodes. Make sure you have at least 3 nodes that you remove from the plant with a sharp knife or sharp secateurs. Just below the node make a very clean cut with your sharp knife. Then remove half the leaves to reduce the surface area for transpiration. If you leave too many leaves on the plant it will start to loose water or wilt and once it gets to a certain point of wilting it will die. Take a plastic seedling tray and fill it with river sand. Make a hole in the soil and place the cutting half way into the soil and cover with the soil. Make sure the cuttings are not too close and have place to grow. After about 5 weeks tip the tray upside down and see if roots are coming out of the bottom of the tray. If yes then you can remove the cuttings and plant in your garden. It is as simple as that. With plants propagated through asexual means you are guaranteed to get the exact replica of the plant you are taking cuttings from compared to sowing seed where each plant may be different. Tissue culture is a means of taking a growing part of the plant and placing it on an agar medium which is a very specialized medium created for different plants under very sterile conditions in a laboratory. Through the use of hormones and divisions that one small growing point can produce millions of plants that are exactly like the parent plant. Orchid culture uses this method to huge success. If you have any questions you know how to get hold of me.
How to plant:
If you are doing any planting whether it be a tree, shrub or groundcover make sure you prepare the hole correctly and place the plant in the hole at the correct depth and spacing. When deciding on how many plants to buy for your garden the easiest way is to measure the garden into meter squares and work out the size of the plant and how many plants you put per meter square. If you buy a groundcover that is in a 2-3 liter growing bag then best to place 7 plants per m2. If you are planting trees then work out how big the tree grows before planting. If you buy a fig tree then realize this tree will grow to 15-20 meters and must not be planted within 5-7 meters of each other. Shrubs generally you plant 3 per meter as in time these will grow to be big plants and if planted too close could result in diseases and fungal problems. You must also take into account that many of these plants will need to be pruned at least once a year so allow space to move in amongst these plants. When planting an area you must prepare it properly. This means turning the soil and adding lots of compost and fertilizer. Level the area so it is neat and ready for planting. Depending on the size of the bag it is best to dig a square hole that ir larger than the bag. Then add some compost mixed with soil and stamp the soil with your boots to make sure the bottom of the hole is level. Ensure when you take the plant out of the bag that it does not lose all its soil. This is very important as it will knock the growth back if all the soil falls away from the roots. Many nurseries often put plants into big bags and when newly planted the roots have not had time to establish so this soil will fall away when you remove the plant from the bag. Once you have removed the plant from the bag then place it in the hole so that the top of the root ball is just above the surface of the soil. The reason for this is that there will be air pockets in the soil so when you water the plant it will sink slightly. You must make sure that the stem of the plant is never below the surface of the soil as this will cause rot of the stem. Once you fill the hole with the soil gently stamp the soil with your boots to stabilize the plant in the hole. If it is a tree or large shrub then best to stake the plant with a wooden stake you can buy from the nursery. Make sure you water the plant well to allow it time to recover and allow its roots to start growing. Make sure you water at least every 2 days till you see the plant producing new growth.
Things to do this month:
- Continue maintaining your lawns as the summer rains have not yet finished. Cut weekly and feed one last time before winter with 5.1.5 granular fertilizer.
- Enjoy the group of plants under the Genus Plectranthus in particular Plectranthus ecklonii , zuluensis and ciliatus which are in full bloom. If you drive around the greater Durban area the one that stands out are the three color forms of Plectranthus ecklonii which are large shrubs of pink, white and purple. It is a very rewarding shrub that flowers always in March for about 3-4 weeks and which requires very little maintenance except after it has finished flowering when you need to cut it back. Its common name is the Large spur flower.
- Plant a groundcover that will do well in winter as well as in the shade. A few good examples are Crassula multicarva, Plectranthus ciliatus, Chlorophytum comosum, Asystasia gangetica and Aristida junciformis. All flower in late autumn and early winter plus seed produced on the grass. Try and plant them in huge sweeps as they give a dramatic display when in numbers.
- Keep an eye out for shrubs that flower in winter that will be in spike and ready to flower in a few months. These plants can become too top heavy and break if we have strong winds or lots of rain. Make sure these plants are staked to stabilize them and also to prevent them from breaking. Do not prune these shrubs until they have finished flowering. Examples would be Leonotis leonorus, Hypoestes aristata, Plectranthus ecklonii, Strelitzia reginae, Bauhinia galpinii and Plumbago auriculata. Some Aloes will produce flower spikes in the next few months so look forward to the winter show of Aloes.
- There are other shrubs that would have flowered in summer and need to be pruned before the onset of winter. Pruning has many benefits: Removal of dead wood, reducing the plant to the size of your garden, removal of diseased growth, induces new growth and creating a design form.
- We have had lovely rain this past few months which has boosted growth especially weeds. Best to remove them physically if they are growing amongst other plants or if in paving spay with roundup. Don’t let these plants go to seed. Mulch your garden either with bark chippings or compost to prevent the weeds growing out of control.
- Great time to do some late summer planting for flowering in winter. Most shrubs and groundcovers planted now will flower this coming winter.
Don’t forget the Open Gardens in Kloof this coming week end. Great time to get ideas on how to display indigenous plants in your garden.
This article is sponsored by Chris Dalzell of Chris Dalzell Landscapes. If you have any questions please email me on: firstname.lastname@example.org