Pot Trees: A Guide

Pot Trees: A Comprehensive Guide to Container Gardening with Trees

Growing trees in pots, also known as container gardening with trees, is a fantastic way to add greenery, structure, and even fruit to small spaces [1]. Whether you have a compact urban garden, a balcony, a patio, or simply want the flexibility to move your trees around, growing trees in pots offers a practical and aesthetically pleasing solution [12, 1]. This guide provides you with all the essential information you need to successfully cultivate thriving trees in containers, covering everything from selecting the right tree and pot to ongoing care and maintenance.

Why Grow Trees in Pots?

There are numerous benefits to growing trees in pots, especially in urban environments [3, 4]:

• Space Optimization: Ideal for small gardens, patios, balconies, and rooftops where ground space is limited [1].
• Flexibility: Easily move trees to different locations to maximize sunlight, provide shelter from harsh weather, or change your garden layout [1].
• Control: Manage soil quality, watering, and fertilization more effectively than in-ground planting [10].
• Aesthetics: Add height, structure, and visual interest to your outdoor spaces, enhancing the overall appeal of your home [1].
• Accessibility: Makes gardening possible for those with mobility issues or limited access to traditional garden spaces [13].
• Food Security: Urban gardening contributes to food security by providing access to fruits [12, 16].

Choosing the Right Tree for Your Pot

Selecting the right tree is crucial for successful container gardening. Not all trees thrive in pots, so it's essential to consider factors like size, growth rate, and environmental needs [1].

Factors to Consider:

• Size and Growth Rate: Opt for dwarf or slow-growing varieties that won't quickly outgrow their containers [1, 25].
• Sunlight Requirements: Choose trees that match the amount of sunlight your space receives. Most vegetables need at least 6 hours of direct sun daily [13].
• Hardiness: Ensure the tree is suitable for your local climate and can withstand the winter temperatures in your area [25].
• Mature Size: Look for trees that will mature at a modest size [8].

Recommended Tree Varieties:

• Japanese Maple (Acer palmatum): Known for their stunning foliage and compact size, perfect for adding color and elegance to your patio [2, 7, 19]. There are many varieties which stay under 10’ [7].
• Olive Tree (Olea europaea): Stylish and drought-tolerant, olive trees thrive in pots and can even produce fruit [2, 32]. Requires full sun [2].
• Crape Myrtle (Lagerstroemia indica): Offers long-lasting summer blooms and attractive bark, ideal for adding color to outdoor entertaining areas [2, 17]. The Pink Velour, Sioux, Acoma, Country Red, or Catawba varieties are recommended for containers [2].
• Hinoki Cypress (Chamaecyparis obtusa): A compact, slow-growing evergreen with a sculptural form, providing year-round interest [2, 7]. Prefers full sun to partial shade and moist, fertile soil [2].
• Amelanchier (Amelanchier spp.): A small tree with white blossom in spring and pretty autumn colours [6, 14].
• Blue Arrow Juniper (Juniperus scopulorum 'Blue Arrow'): A narrow, upright evergreen that's perfect for tight urban spaces or creating privacy on decks and patios [2]. Requires at least six hours of full sun and grows well in any type of well-drained soil [2].

Fruit Trees in Pots:

Many fruit trees can also be successfully grown in containers, providing fresh produce even in limited spaces [11, 24].

• Dwarf Apple Trees: A restricted apple tree grown on a semi-dwarfing rootstock is suitable for growing in pots [1].
• Patio Peach Trees: Grow well in containers [11].
• Dwarf Pomegranate: Ideal as they cope well in containers while still offering flowers, fruit and interest even in the most compact of spots [11].

Selecting the Right Pot

The container you choose plays a vital role in the health and growth of your tree. Here’s what to consider:

Factors to Consider:

• Size: Choose a pot large enough to accommodate the root ball of your tree, with extra room for growth [1]. A general guide for trees in pots is to start with a pot twice the width and depth of the root ball and finish with a large pot of at least 60cm wide at the top and 55cm deep [9].
• Drainage: Ensure the pot has plenty of drainage holes to prevent waterlogging, which can lead to root rot [1, 9].
• Material:
  • Terracotta: Provides good aeration but can dry out quickly and be heavy to move [1, 28]. Frost-proof terracotta pots are heavy, providing extra stability to prevent trees blowing down in windy weather [1].
  • Plastic: Lightweight and retains moisture well, but may not be as aesthetically pleasing [30].
  • Wood: Offers a natural look and good insulation but can rot over time [20].
• Weight: Consider the weight of the pot, especially if you plan to move it. Use a furniture or plant dolly if the plants need to move with the seasons [13].
• Aesthetics: Choose a container that complements your garden style and personal taste [1].

Tips for Pot Selection:

• Do not put a small tree in a very large container; instead pot up the plant in stages, finishing with a minimum final container size of about 45cm (18in) [1].
• Place some medium stones or broken pieces of an old clay pot in the bottom to aid in drainage [8]. Adding gravel to the bottom doesn't improve the drainage [9].

Planting Your Tree

Proper planting is essential to give your tree the best start in its container [8].

Steps for Planting:

1. Prepare the Pot: Ensure the pot is clean and has adequate drainage holes [1, 9].
2. Add Soil: Use a high-quality, well-draining potting mix specifically formulated for trees in containers [10, 18]. Do not use soil directly from the garden [18]. Most garden soils are too heavy, can become easily waterlogged and compacted, and harbor disease and insects [10].
3. Position the Tree: Carefully remove the tree from its nursery container and gently loosen any circling roots [8]. Place the tree in the center of the pot, ensuring the top of the root ball is level with the soil surface [8]. Do not put the tree any deeper in the soil than the tree was growing in the field. In other words, cover the roots but do not place soil around the trunk of the tree [8].
4. Fill and Settle: Fill the remaining space with potting mix, gently firming the soil around the base of the tree [8].
5. Water Thoroughly: Water the newly planted tree thoroughly until water drains from the bottom of the pot [8].

Caring for Your Potted Tree

Proper care is essential for maintaining the health and vigor of your container-grown tree [18].

Watering:

• Trees in containers dry out more quickly than those in the ground, so regular watering is crucial [1, 18].
• Water thoroughly whenever the top inch of soil feels dry [2].
• Ensure the full depth of the compost is moistened [1].
• In hot weather, you may need to water daily [21].
• Water plants thoroughly in the morning or evening, making sure the water soaks through to the plants' roots [20].

Fertilizing:

• Container plants need regular fertilization as nutrients are leached out of the soil with watering [13].
• Use a slow-release fertilizer or a liquid feed at regular intervals during the growing season [1, 18]. Trees in pots will benefit from some Natural Tree Liquid Feed fertiliser, spring is the best time to add this when the growth is fresh and vigorous [5].
• Follow the instructions on the fertilizer package for proper dosage [9].

Pruning:

• Prune your tree to maintain its shape, remove dead or damaged branches, and encourage healthy growth [5].
• Most patio trees will require little pruning as they do not have a great deal of vigour, however, some light pruning may be beneficial. Pinching out tips of fresh growth and cutting off any dieback is sensible [5].
• Some varieties will have individual pruning requirements [5].

Repotting:

• As the tree grows, it will eventually need to be repotted into a larger container [9, 32].
• Repot every few years, or when you notice the roots becoming crowded [2].
• Every couple of years or so, you'll notice your tree dries out more quickly and lacks vigour. This tells you that attention is required. Un-pot the plant and trim the outer 10mm of the root ball with a sharp knife or your secateurs to stop the roots from growing around the root ball. Re-plant into the same or a larger container with enough potting mix so the top of the plant sits about 3 or 4cm below the rim [9].
• Root pruning slows down the growth of the container tree and likely will add to the life of the tree [8].

Winter Care:

• In colder climates, protect your container trees from freezing temperatures [1].
• Wrap the container with bubble wrap or burlap to insulate the roots [1].
• Move the tree to a sheltered location, such as a garage or shed, or move the container tree indoors when winter weather hits [25, 18].

Other Tips:

• Keep containers free of weeds aided by a bit of mulching will help the trees flourish [5]. We would not advise planting lots of flowers in with the tree as they will compete for water and nutrients [5].
• In exposed gardens, plants in containers will need protecting during winter as the roots growing near the edges are vulnerable to freezing temperatures. Wrap the container with bubble wrap or hessian, held securely in place with twine [1].
• Raise containers off of hot cement with plant trivets, wood, or bricks [13].
• Mulch in the pots to help regulate soil temperature and retain moisture [2].

Troubleshooting Common Problems

Even with the best care, you may encounter some challenges when growing trees in pots.

• Yellowing Leaves: Could indicate overwatering, underwatering, or nutrient deficiency. Adjust watering and fertilizing as needed [18].
• Drooping Leaves: Often caused by underwatering or heat stress. Ensure adequate watering and provide shade during the hottest part of the day [18].
• Pests and Diseases: Monitor your trees regularly for signs of pests or diseases. Treat promptly with appropriate organic or chemical controls [18].
• Root Rot: Caused by poor drainage and overwatering. Ensure proper drainage and allow the soil to dry out slightly between waterings [9].

Conclusion

Growing trees in pots is a rewarding way to bring the beauty and benefits of trees to any space, regardless of size. By selecting the right tree and pot, providing proper care, and addressing any issues promptly, you can enjoy a thriving container garden for years to come [35].

Next Steps:

• Choose the type of tree that you want to grow in a pot, taking into account your climate and the amount of space you have available.
• Select a pot that is the appropriate size for your tree, and make sure it has drainage holes.
• Gather the necessary supplies, including potting mix, fertilizer, and pruning shears.
• Follow the planting and care instructions outlined in this guide.
• Regularly inspect your tree for signs of pests or diseases, and take action as needed.

With a little planning and effort, you can create a stunning and sustainable pot tree garden that enhances your living space and connects you with nature.