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What’s in Bloom? May at RBG

April 30, 2024

What Blooms in May?

Note: this is a general guide of what typically blooms this month at RBG. Bloom periods may vary by up to 2 weeks. For the best view of what’s blooming right now at RBG, see the current photos on RBG’s Instagram, or find the “Bloom Watch” section on the What’s in Bloom page.

In May, the gardens burst to life with a rainbow of blooms! 

Trees and shrubs are the stars of the show at the Arboretum, with individual trees scattered throughout Hendrie Park, Rock Garden, and Laking Garden. Early in the month, walk beneath mid and late-season varieties of Magnolia. Look out for cultivars with unusual yellow blooms such as Magnolia ‘Butterflies’, whilst Flowering Quince and various viburnums are putting on a beautiful display. 

Throughout the Rock Garden early perennials including Bleeding Heart, Double Bloodroot, and Bluestar flourish. 

  • creamy yellow magnolias beginning to bloom
  • pink Viburnum
  • bleeding heart flowers
  • white bloodroot in bloom

Pictured, left to right: Magnolia, Viburnum, Bleeding Heart, Double Bloodroot

Following closely behind, the gardens transition to the vibrant pinks of Redbud, while Flowering Quince and Serviceberry brighten up the garden, alongside the early-blooming Hyacinth Lilac. Stunning trilliums can be found along the nearby nature trails. Inside Rock Garden, Moss Phlox, Lungwort, and Bugloss dot the winding paths. Pops of colour can be found throughout Hendrie Park with bright bulbs and perennials including daffodils and Virginia Bluebells.

  • Close Up Of Redbud Blooms In Arboretum With Clear Blue Sky Backdrop
  • wooden bench below a magnolia tree with soft yellow blooms
  • Red Flowering Quince
  • small blue-purple flowers

Pictured, left to right: Redbud, Daffodils and Magnolia tree, Flowering Quince, Bugloss

May* typically brings peak bloom for the lilacs, as their sweet scent of the Katie Osborne Lilac Collection fills the Arboretum. At Rock Garden, beautiful trees and shrubs including Fragrant Sumac, Japanese Kerria and Crabapple put on a fantastic spring show, while early blooming perennials dazzle out front. In Laking Garden, end-of-month visitors can spot the early Bearded Iris and tree peonies, a preview to the larger show to come in June. 

*Bloom times vary from year to year as they are influenced by many natural events including temperature and climate. For the most up-to-date information and images of what’s currently blooming in the gardens, check out RBG’s Instagram feed.

  • Purple Lilac Bunch In Bloom
  • white flowering crabapple tree
  • rainbow of standard dwarf bearded irisesrises
  • large pink tree peonies at the front entrance of Laking Garden

Pictured, left to right: Lilac, Crabapple, Dwarf Iris, Tree Peony

May Favourites

Pink Saucer Magnolia Flowers In Bloom


Multiple varieties bloom throughout early to mid-May.

Major collection bloom in the Arboretum. Trees also found at Rock Garden, Laking Garden and Hendrie Park. 

Lilac Tree In Foreground Overlooking People Walking Along A Path In Distance


The Katie Osborne Lilac Collection typically reaches peak bloom in late May, and sometimes early-June, with some early varieties blooming mid-May 

Major collection found in the Arboretum. Lilacs also found in Hendrie Park.

Plants that typically flower in May at RBG

  • Annual bulbs – Tulips
  • Redbud* 
  • Magnolia* 
  • Dogwood 
  • Crabapple 
  • Lilac 
  • Spring Ephemerals 
  • Iris (dwarf and early bearded varieties) 
  • Coral Bells 
  • Hosta 
  • Tree Peony* 

*These plants have short bloom times and are very weather dependent. Check our social media feeds closer to bloom time for updates. 

Blooms by Season

Plants of interest are ever-changing in RBG’s five cultivated garden areas and nature sanctuaries. Learn what’s blooming now or see the blooms calendar for a rough estimation of what to expect each season.