Gardening How-to Articles

A New Tree Bed Garden

Tree beds offer great opportunities for city dwellers to exercise their green thumbs. Passersby appreciate seeing flowers instead of trash around street trees; they may curb their dogs in response. Wilting flowers in the tree bed provide a good reminder to water. As long as gardeners remember that the tree's health always comes first, they can choose from a large palette of annuals, perennials, and bulbs to beautify tree beds.

A Tree Bed Garden


  1. Thymus praecox (creeping thyme)
    3 inches tall; 12 inches wide
    This mat-forming tough groundcover has fragrant leaves and clusters of tiny deep pink flowers (attractive to bees) that bloom June through July; let spill onto sidewalk to soften edges.
    Zones 4 to 8.
  2. Sedum'Autumn Joy' (stonecrop)
    18 to 24 inches tall; 18 inches wide
    The succulent foliage forms a tidy clump, and long-lasting late-summer flowers start pink and mature to rusty red, followed by showy seed heads.
    Zones 3 to 10.
  3. Asclepias tuberosa (butterfly weed)
    12 to 24 inches tall; 18 inches wide
    Spectacular umbels of fiery-orange summer flowers attract monarchs and other butterflies; the narrow green leaves are also a food source for their caterpillars.
    Zones 3 to 9.
  4. Scabiosa columbaria 'Butterfly Blue' (pincushion flower)
    12 to 18 inches tall and wide
    Showy, profuse, butterfly-luring lavender-blue flowers bloom singly on stiff stems from April until frost; prefers well-drained soil and full sun.
    Zones 5 to 9.


  1. Zinnia angustifolia Star Series (zinnia)
    9 to 12 inches tall and wide
    Drought-tolerant butterfly magnets, these yellow, white, and orange flowers bloom nonstop from June to frost and don't fade in summer heat like other zinnias.
  2. Tropaeolum majus 'Dwarf Jewel Mix' (nasturtium)
    12 to 18 inches tall and wide
    Long-stalked rust, orange, and yellow flowers bloom among bushy round foliage from June through October and delight in poor soil. Easy to grow from seed and bloom in just six weeks.

Spring Bulbs

Slip some spring bulbs into the tree bed in fall to provide a flush of color in late winter and early spring before the perennials fill out.

  1. Eranthis hyemalis (winter aconite)
    3 to 6 inches tall and wide
    One of the earliest bulbs to bloom, the clumps of little yellow cup-shaped flowers will brighten the tree bed in February and March; plant in groups.
    Zones 4 to 7.
  2. Galanthus nivalis(snowdrop)
    6 inches tall; 3 inches wide
    Nodding white blooms on single stems poke up through the snow in March to herald the approach of spring; great mixed with winter aconite.
    Zones 3 to 7.
  3. Tulipa saxatilis(candia tulip)
    6 to 9 inches tall and wide
    Native to rocky Crete, each stem of this tough, compact species tulip produces up to four stunning rose-lilac flowers with yellow bases in April.
    Zones 3 to 8.

The most common mistake made by tree bed gardeners is raising the soil level. Added soil can suffocate tree roots, and moist material piled against bark leads to rot and infection from pests and diseases. Roots can also be damaged by vigorous digging. Instead, use a hand cultivator to gently scratch an inch or two of compost into compacted dirt. The organic matter will break down without raising the bed's level and will gradually improve the tilth of the soil. To conserve moisture and prevent weeds, you can add mulch, leaving a clear space around the tree's trunk. Consider building a safe tree guard (no pointy edges) around the bed that allows rainwater to flow in off the sidewalk.

Many cities are enlarging their tree canopies to clean and cool the air through civic tree-planting programs; for example, New York City and Los Angeles each have initiatives to plant a million new trees (see and Newly planted street trees welcome sunloving companions as long as they're not too thirsty-tree bed plants should never be allowed to outcompete the tree for water! Listed here are fairly tough, drought-tolerant plants that enjoy full sun and can stand up to life on the street.

Robin Simmen is a former director of Brooklyn Botanic Garden's community greening programs.


  • Jo Foster October 30, 2015

    After three years of “curbing my enthusiasm”, attending your lovely workshops and others such as the forestry people on making affordable tree bed guards, researching plants and practicalities, I have just now concluded that I won’t be able to proceed. I have been unable to find out how to get anything between the expensive iron fences offered by the Tree Trust and making a cheaper wooden one which would probably not be approved in my historic neighbourhood. I am asked to “submit my design” together with a signature from my Co-op Board. Do you know of any affordable successful existing solutions? Everything ready-made in retail stores is too tall (min 4ft) or too small (1ft). An entrepreneur could do well offering 2ft components!

  • BBG GreenBridge Staff April 1, 2014

    Hi, Elizabeth—You’re absolutely right to be concerned that the woody perennials you mention will compete for water and space with your young tree. They will. Such a tree, especially in the first few growing season after planting, needs an inch of rain or 20 gallons of water—per week! The most important thing you can do is to provide water and mulch. When it comes to gardening in street tree beds, sometimes it’s best to “curb our enthusiasm!”

  • Elizabeth Meister March 20, 2014

    Hi, I will be having a street tree bed dug in April and am incredibly excited by this new gardening space! I am on the southern-facing side of the street and there aren’t many trees around, so I have lot of sun. I was interested in putting in a dwarf lilac and or a butterfly bush; also some Cornus sericea ‘Arctic Fire’ for winter interest. Besides space constraints (I know I want to plant more than I can!), would you consider any of these to be too competitive for a new tree? The parks person who came by to mark the spot said I didn’t need to worry about that, but your article makes me think I should. I appreciate any input as I have years of pent-up gardening threatening to unleash itself on my tree bed, and neighbors . . .

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