Want to add some significant greenery and even small trees to your patio, deck, or balcony? Large outdoor planters make it possible! While you won’t be growing towering oaks, there are many impressive large plants and small trees that thrive in containers, adding height, structure, and a touch of nature to your outdoor living spaces. Understanding their root space requirements is crucial for their long-term health and success. Let’s explore some suitable options and their needs.

Choosing the Right Plants for Large Planters:

When selecting large plants or trees for containers, it’s important to consider a few factors beyond just their size:

• Dwarf or Slow-Growing Varieties: Opt for varieties that are naturally smaller or grow at a slower rate, making them more manageable in a confined space.
• Adaptability to Container Life: Some plants simply don’t do well in pots due to their extensive or deep root systems. Choose those known to adapt to container environments.
• Your Climate (USDA Hardiness Zone): Ensure the plant is suitable for your local climate and can withstand the temperature extremes in your region.
• Sunlight Exposure: Match the plant’s light requirements (full sun, partial shade, full shade) to the conditions on your patio or deck.

Suitable Large Plants and Small Trees for Containers:

Here are some popular and aesthetically pleasing options for large outdoor planters, along with general guidelines on their root space needs:

Small Trees:

• Japanese Maple (Acer palmatum – dwarf varieties): These beautiful trees come in various colors and leaf shapes. Dwarf varieties like ‘Bloodgood Dwarf’ or ‘Shaina’ are excellent choices.
  • Root Space: Aim for a planter that is at least 24-36 inches in diameter and depth for mature dwarf varieties. A container of 20-30 gallons is a good starting point.
• Dwarf Citrus Trees (Lemon, Lime, Orange, Kumquat): Enjoy fresh citrus even in cooler climates by growing dwarf varieties in pots.
  • Root Space: Start with a container of at least 15-20 gallons and be prepared to repot into a larger 25-30+ gallon container as the tree grows. The planter should be at least 20-24 inches deep and wide.
• Olive Tree (Olea europaea): These elegant trees are drought-tolerant and add a Mediterranean feel. Choose a dwarf or semi-dwarf variety.
  • Root Space: A container of 20-25 gallons or larger, with a minimum depth and diameter of 24 inches, is recommended for mature specimens.
• Crepe Myrtle (Lagerstroemia indica – dwarf varieties): These offer beautiful summer blooms and attractive bark in the winter. Look for dwarf cultivars like ‘Tonto’ or ‘Lipan’.
  • Root Space: A container of at least 20 gallons with a depth and diameter of 20-24 inches is suitable for dwarf varieties.
• Windmill Palm (Trachycarpus fortunei): This cold-hardy palm can add a tropical touch to your outdoor space.
  • Root Space: Requires a substantial container, at least 24-36 inches in diameter and depth, or a 30-50+ gallon pot for mature growth.
• Boxwood (Buxus): While often used as shrubs, certain boxwood varieties can be grown as small, elegant trees in containers.
  • Root Space: Depending on the desired size, aim for a container that is at least 18-24 inches in diameter and depth, or a 15-25 gallon pot.

Large Shrubs:

• Hydrangea (certain varieties): Many hydrangea varieties thrive in containers, offering stunning blooms. Choose compact or dwarf cultivars.
  • Root Space: A container of at least 15-20 gallons with a depth and diameter of 18-24 inches is generally sufficient.
• Rhododendron and Azalea (dwarf varieties): These acid-loving shrubs offer beautiful spring flowers. Select dwarf or compact varieties.
  • Root Space: Similar to hydrangeas, a 15-20 gallon pot with adequate depth and width should suffice.
• Camellia: These evergreen shrubs boast beautiful flowers in the fall, winter, or spring.
  • Root Space: Start with a 15-gallon container and be prepared to move to a 20-25+ gallon pot as it matures. The planter should be at least 20 inches deep and wide.
• Arborvitae (dwarf varieties): These evergreen conifers provide year-round structure. Choose dwarf, columnar varieties like ‘Emerald Green’ or ‘Little Giant’.
  • Root Space: A container of at least 18-24 inches in diameter and depth, or a 20-30 gallon pot, is recommended.
• Rosemary (large varieties): While technically a herb, large rosemary bushes can take on a tree-like form and do well in containers.
  • Root Space: A container of at least 15-20 gallons with a depth and diameter of 18-24 inches is suitable.

General Guidelines for Root Space:

• Depth is Key: Ensure the planter is deep enough to accommodate the plant’s taproot or main root system.
• Width Matters: Adequate width allows for lateral root growth and overall stability.
• Bigger is Better (Generally): When in doubt, opt for a slightly larger container. It’s better to have too much space than too little.
• Consider the Mature Size: Always factor in the plant’s potential growth over several years.

Other Important Considerations for Large Container Plants:

• Drainage: Excellent drainage is crucial. Ensure your planter has ample drainage holes.
• Potting Mix: Use a high-quality potting mix designed for containers.
• Watering: Container plants dry out faster than those in the ground, so regular watering is essential.
• Fertilizing: Provide regular fertilization, especially during the growing season.
• Winter Protection: In colder climates, you may need to provide winter protection for the roots, such as wrapping the container or moving it to a sheltered location.
• Weight: Large planted containers can be very heavy. Consider this when choosing a location, as they may be difficult to move once filled.

By selecting the right large plants or small trees and providing them with adequate root space and care, you can create stunning and impactful container gardens that will thrive for years to come.