Introduction
This article covers all aspects of caring for and maintaining mother plants, including root and stem pruning, as well as rejuvenating old mother plants.
“Tired of huge, bulky ‘mothers’ that take up too much space? As I’ve found, a fully rooted bonsai mother plant, if well-fed, only takes up about 8×8 inches (20×20 cm).”
Typical Bonsai Mother Plant
A typical bonsai mother plant can produce 10 to 30 good clones every two weeks under a high-intensity discharge lamp (HPS/MH) or every 20 days under a fluorescent lamp. This means that under lights covering a total area of 48×24 inches (120×60 cm), 18 mother plants can produce over 9,500 clones per year.
We’re not talking about intensive production here, but this example shows the simplicity and efficiency of the system. What does this offer a grower? It allows you to preserve a good selection of different strains in a relatively small area. If you want to grow just one mother plant, all it needs is consistent life cycle support.
Creating a Mother Plant
Let’s start with creating a mother plant—it’s simple. You’ll see that by cutting off small sections, you won’t harm the plant much, and it will become more resilient and look better. Take one or two strong plants to make your mother. Remember, you’ll need to prune this mother plant 4 to 18 times a year for 3 to 15 years, so choose the strongest plant.
Take a fully rooted clone after pruning and plant it in a square pot with an area of about 2.5×2.5 inches (6 cm2). I’ve found that square pots are much more convenient for root pruning, as you’ll see later.
Rooted Clone at the Optimal Size for Creating a Mother Plant
Grow it for a few days until it starts rooting, then cut off the top, leaving 3–4 side shoots.
Mother Plant with the Top Cut Off (Side and Top Views)
These small branches will form the main “skeleton” of your mother plant. Ideally, as they grow, they should form an open bowl shape. The second top will grow faster, and when its stems reach over 5 inches (12 cm), pinch or cut off all tips that have grown longer than this. This allows the next pair of shoots to “catch up” in a day or two. Then pinch them the same way. This helps the side leaves take the desired shape. Anything growing in the center of the formed bowl should be trimmed.
Now you have 6 to 8 main shoots. When they reach 4–6 inches (10–15 cm) in length, these will be your first clones. Cut the shoots just above the first lower leaf. After this pruning, the mother plant will be a bit larger than after the first cut, but the main stems will strengthen and thicken.
Now it’s time to transplant the mother plant into a larger pot. The optimal pot area is about 3×3 inches (8 cm2). Now the number of main shoots will be 12–16, plus other shoots from the lower ends of the stems, so in total—30 or more shoots. Any thin shoots, including those growing in the center, should be trimmed.
All Stages of Bonsai Mother Plant Growth
- The first plant is a cutting with the top removed.
- The second plant has already had clones taken twice and is ready to be transplanted into a pot with an area of 8 cm2. As you can see, it’s not much bigger than the previous one; it’s best to transplant after the first round of clone cutting.
- The third plant is in an 8 cm2 pot, 12 clones have already been cut, and 2 are left to show where to cut a clone.
- The fourth plant is a five-year-old mother plant, from which 32 clones have been taken and weak shoots pruned. Since three months old, it has grown in a 1-liter pot.
Notice that all the plants have an open center, allowing light to penetrate between the leaves and illuminate the plant from the outside. If you want to take good clones, you should thin the plant and maintain this shape. While the mother plant is forming, use only water without fertilizers. Before starting to feed, transplant the plant into its “final” 1-liter pot and take one or two rounds of clones.
Basic Care and Maintenance of Fully Formed Mother Plants
Mother plants need sufficient fertilizer to stay healthy. Feed the plant twice a month with half the recommended dose of fertilizer. It’s best to use mineral fertilizers with an NPK ratio of 6–2–4, but this isn’t critical. This will keep the plant in good shape without overfeeding. If you want a faster harvest, you can use a full dose of fertilizer a few times.
Every 2–4 weeks, you need to take clones, even if you don’t need them, to maintain the plant’s shape and size. Because of such frequent pruning, the plant may lack macro-nutrients, so every month spray the leaves with a fertilizer solution, such as Maxicrop. But do this as needed, not strictly on schedule, paying attention to the plant’s appearance.
It’s very important for the grower to constantly observe the plant to know when it’s healthy and needs nothing, and when the first signs of nutrient deficiency appear. First, the plant may lack magnesium, even if you used dolomite lime in the compost. If magnesium is lacking, water and spray the plant with a solution of 1 oz (30 grams) of Epsom salt per 1.2 gallons (4.5 liters) of water.
Root pruning is necessary 1–2 times a year, depending on how intensively the plant is fed and the quality of your water. It’s almost impossible to remove accumulated salts from the roots. Temporary over-fertilization is acceptable, but you must not allow gradual salt crystallization and carbonate buildup. If your water is heavily mineralized, I recommend getting a small reverse osmosis filter to purify water for your bonsai mother plant and clones.
Root Pruning and Rejuvenating the Mother Plant
The method for root pruning a mother plant for regular maintenance and for rejuvenation is the same.
Here, we take a seven-year-old mother plant whose roots haven’t been pruned for about a year. The plant was deliberately neglected for the last 10 weeks to show you the recovery process. During this time, it was on a “diet”: only purified water and no other feeding. This shows how resilient the plant is and how much you can neglect it and still bring it back. However, I don’t recommend neglecting your plant for long, as it may die.
7-Year-Old Mother Plant with Roots Not Pruned for About a Year
As you can see, there’s still some fertilizer left in the compost. First, prune all branches except the main ones. Leave 1–2 thin shoots on each branch so the branches continue to draw nutrients and stay alive. If you cut off all shoots and buds, there’s a high chance the plant will die within 1–2 months. Don’t cut off the shoots, even if they’ve yellowed from nutrient deficiency—they’ll green up again as soon as new roots start to form.
Mother Plant After Pruning All Non-Main Branches
Next, prune the root system by 0.8 inches (2 cm) from the sides and 1 inch (2.5 cm) from the bottom. After removing the old compost, the root system size is reduced from 4.5×4.5×4.5 inches (11.5×11.5×11.5 cm) to 3x3x3.5 inches (7.5×7.5×9 cm).
Pruning the Root System from the Sides and Bottom
This removes about two-thirds of the old soil. Use good, strong substrate for transplanting, and within 1–2 days the mother plant will start growing in the new compost. Note: It’s very important to make sure there are no air pockets, so when adding soil, use a pencil or small trowel to gently compact the soil.
Place the bottom of the root system on a 0.8-inch (2 cm) layer of compost, then fill the pot with compost around the sides, and cover the roots with 0.2–0.4 inches (0.5–1 cm) of compost on top. This means you need to prune the mother plant’s roots by more than 0.4 inches (1 cm) per year, planting it 0.2 inches (0.5 cm) deeper in the compost each time.
Back in the Pot with Fresh Compost, Ready to Grow Again
In the last photo, the plant is shown 12 days after root and top pruning. There are already enough strong main shoots that can yield about 10 clones. If you want to speed up its development and get the maximum batch of clones, put the mother plant under a sodium lamp (HPS/MH). Even under these conditions, recovery won’t take long.
Mother Plant 12 Days After Root Pruning and Transplanting
After a couple of years, you can cut the root system vertically, splitting the plant in two, as the side branch will have its own root system. Using this method, the roots will constantly regenerate, and the main trunk will slowly thicken. This allows the mother plant to live for many years.
The second mother plant I selected lived for 15 years thanks to this method. If you want to keep the plant for a long time but in a smaller pot, say a 2.5-inch (6 cm) pot, prune the roots the same way as for a plant in a 1-liter pot, but by 0.2 inches (0.5 cm) on each side. I grew male plants in such a pot for about 5 years.