While smaller plants and flowers are common choices for outdoor containers, don’t underestimate the impact of growing larger plants, shrubs, or even small trees in substantial outdoor flower pots. These additions can create a focal point, provide shade, add privacy, and bring a sense of established permanence to your patio, deck, or balcony. However, selecting the right plants and providing adequate root space are crucial for their long-term health and visual appeal. Let’s explore some suitable options and their typical root space requirements.

Choosing Large Plants for Impact:

For a dramatic display, consider these larger plant options that can thrive in spacious containers:

• Banana Plants (Dwarf Varieties): While some banana plants can become enormous, dwarf varieties like ‘Dwarf Cavendish’ or ‘Super Dwarf Cavendish’ are well-suited for large pots. They offer lush, tropical foliage and can even produce fruit in warm climates. Root Space: Aim for a container at least 20-25 gallons in size.
• Canna Lilies: These bold plants boast striking foliage in various colors (green, bronze, variegated) and vibrant, showy flowers in summer. Their upright growth habit makes them ideal for adding height. Root Space: A container of 10-15 gallons is generally sufficient.
• Elephant Ears (Colocasia/Alocasia): With their oversized, dramatic leaves, Elephant Ears make a bold statement. Choose varieties that stay within a manageable size for containers. Root Space: Provide at least a 15-20 gallon pot for larger varieties.

Selecting Shrubs for Structure and Beauty:

Shrubs can provide year-round interest and structure to your container garden:

• Dwarf Conifers (e.g., Dwarf Alberta Spruce, Mugo Pine): These evergreen shrubs offer year-round greenery and a formal or natural look. Choose dwarf varieties that won’t outgrow their containers too quickly. Root Space: Start with a 15-20 gallon pot for smaller dwarf varieties and go larger (25+ gallons) for more mature specimens.
• Hydrangeas (Smaller Varieties): Many compact or dwarf hydrangea varieties, like ‘Little Lime’ or ‘Bobo’, thrive in large containers. They offer beautiful blooms in various colors depending on the variety and soil pH. Root Space: A container of at least 15-20 gallons is recommended.
• Japanese Maples (Dwarf or Semi-Dwarf): These elegant trees come in a range of stunning foliage colors and graceful shapes. Opt for dwarf or semi-dwarf cultivars that are slower growing and more suited to container life. Root Space: Start with a 20-25 gallon pot and be prepared to upgrade to a larger size (30+ gallons) as the tree matures.
• Boxwood (Buxus): These classic evergreen shrubs are excellent for creating formal shapes or providing a backdrop in mixed plantings. Choose varieties based on your desired size and shape. Root Space: A 10-15 gallon pot is suitable for smaller boxwoods, while larger specimens will need 20+ gallons.
• Camellias: Offering beautiful, rose-like flowers in late winter or early spring, camellias can thrive in large containers, especially in regions with mild climates. Root Space: Provide a pot that is at least 15-20 gallons.

Growing Small Trees in Containers:

Believe it or not, some small trees can flourish in large outdoor pots, adding significant impact to your space:

• Japanese Maples (Larger Varieties): While dwarf varieties are great, even some larger growing Japanese Maples can be successfully grown in very large containers (30+ gallons), although their ultimate size will be somewhat restricted.
• Citrus Trees (Dwarf Varieties): Dwarf citrus trees like lemons, limes, oranges, and kumquats are popular choices for containers. They offer fragrant blossoms and delicious fruit. Root Space: Start with a 15-20 gallon pot and repot to a larger size (25+ gallons) as they grow.
• Olive Trees (Olea europaea): With their silvery-green foliage and Mediterranean charm, olive trees adapt well to container life. Choose a sunny spot and provide excellent drainage. Root Space: A container of at least 20-25 gallons is necessary for a mature olive tree.
• Crape Myrtles (Dwarf Varieties): Some dwarf crape myrtle varieties offer beautiful summer blooms and attractive bark, making them suitable for large pots. Root Space: Aim for a 20-25 gallon container.
• Certain Fruit Trees (Dwarf/Semi-Dwarf): With careful selection, you can even grow dwarf or semi-dwarf fruit trees like apples, pears, or cherries in large containers. Look for varieties specifically grafted for smaller size and container growing. Root Space: This will vary greatly depending on the specific fruit tree, but expect to need at least a 25-gallon pot, and potentially larger.

General Guidelines for Root Space:

• Start Big Enough: Choose a container that seems proportionally large to the plant’s current size. Underestimating the root space can lead to stunted growth and the need for frequent repotting.
• Allow for Growth: As a general rule, select a pot that is at least 2-3 inches wider in diameter than the plant’s root ball. For long-term container growing of larger plants, you’ll likely need containers that are 15 gallons or larger.
• Consider Mature Size: While container growth will limit the ultimate size of your plant, research the typical mature size of the variety you choose and select a pot that will accommodate its root system for several years before requiring repotting.
• Drainage is Key: Regardless of size, ensure your large outdoor pots have excellent drainage to prevent root rot.

Growing large plants, shrubs, and even small trees in containers can bring a whole new dimension to your outdoor spaces. By selecting appropriate varieties and providing ample root space, you can create stunning and long-lasting container gardens.