Grow Rosemary as a Tree to display it indoors with style and also have unlimited harvest year round of this culinary herb.
Growing rosemary as a tree is a rewarding gardening project. Not only will doing this bring a large version 😃 of this aromatic herb to your space and give you an ample harvest for the kitchen for cooking or cocktails 🍸, but having a rosemary topiary also adds a decorative touch, especially during the holiday season!
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How to Grow Rosemary as a Tree
1. Be Patient
Rosemary needs and takes time to grow, and you need to be patient till the trunk grows to be “Woody.” You can also purchase a well-grown rosemary plant, also sold as a “Rosemary topiary” (2-3 feet tall), from a garden center or online.
2. Go for the Right Variety
Either choose a young rosemary plant or get a mature one with a straight, central stem. This will be the “trunk” of your miniature tree. Some of the best types for this job are:
- Tuscan Blue: This variety is known for its upright growth habit and strong, straight stems, making it ideal for training into a tree shape.
- Miss Jessopp’s Upright: Another excellent choice for a bonsai-like appearance, this variety has a naturally upright growth habit and robust stems.
- Blue Spires: This variety is known for its vigorous growth and sturdy stems, which can be easily trained into a desired shape.
- ARP: Recognized for its cold hardiness, the ‘ARP’ variety also features a robust, woody structure suitable for shaping.
- Gorizia: Known for its large leaves and thick, woody stems, Gorizia is an excellent choice for creating a rosemary tree.
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3. Pruning the Plant to Make it Appear As a ‘Tree’
Do not start pruning the plant right from the beginning when it is young, let it grow old and establish. Wait till it reaches a height of about 1.5-2 feet.
- Initial Pruning: Begin by identifying the main stem of your rosemary plant, which will serve as the main stem of your upcoming rosemary topiary. Look for any branches or leaves growing along the lower part of this stem.
- Creating the Trunk: Carefully trim these lower branches and leaves using clean, sharp pruning shears. This exposes a portion of the stem, creating the appearance of a tree trunk. The trunk height depends on your preference and the size of your plant. Generally, exposing 2 inches of the bare stem is a good starting point for young plants.
- Gradual Process: If your plant has a lot of lower growth, it might be necessary to do this gradually over several months to avoid shocking the plant.
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4. Maintaining the Canopy or the Top Growth
Once you have established the main stem, focus on the top of the plant. Regularly trimming the top helps to encourage bushier growth, which is crucial for forming the canopy.
- Pruning Technique: When pruning the top, cut just above a leaf node (the point where the new growth appears). This will encourage the plant to grow two new branches from that node, increasing the branch structure.
- Shaping it: As new growth appears, shape it by pruning to maintain a rounded or conical form, mimicking the shape of a topiary or miniature tree.
How often you need to prune depends on the growth rate of your plant, but generally, light pruning every few weeks to months is sufficient.
- Support if Required: Use a sturdy stake at this stage to ensure the plant is properly supported to take the top heavy weight of the foliage.
Pro Tip: Regularly inspect your rosemary tree for any unwanted growth along the trunk or branches that disrupt the desired shape. Removing too much at once can stress the plant – so do it slowly and do it gently.
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5. Feed Often but Less
Boosting the plant’s growth is essential – rather than fertilizing it once a month with a liquid feed or applying a slow release fertilizer once during the growing season, it is a great idea to dilute the feed to 1/4 or 1/6 of its recommended dose and use it every two-three weeks. This will promote growth, helping it achieve a good height.
6. Keep in a Right Sized Container
If you want this herb to grow like a tree, then it is essential you do not keep it in a container that is way too large or way too small. A slinky pot one size bigger than the plant’s root ball is nice.
Quick Maintenance Tips for Rosemary as a Miniature Tree
- Place the plant in a location with plenty of sunlight- every day – 5 to 6 hours minimum (or as much as possible).
- Water it deeply but infrequently, allowing the soil to dry out slightly between watering spells, as rosemary doesn’t like wet feet.
- During the holiday season, decorate it for a festive look.
- Re-pot every couple of years to provide fresh soil and encourage growth.
- Keep it safe from cold drafts or harsh winters – move it indoors in such conditions. For hot climates, keep it protected from the constant sun exposure, especially in the afternoon.