Why: This region, Warwickshire and Worcestershire in the north, through Gloucestershire and Oxfordshire, down to Bath and Wiltshire in the south, spans nearly 800 square miles of some of the most beautiful countryside in the U.K., and is designated one of 38 Areas of Outstanding Natural Beauty in England and Wales. With its rolling hills and valleys, the Cotswolds is the third-largest protected landscape in England and Wales after the Lake District and Snowdonia. In the 1930s, 40 percent of the Cotswolds was covered in wildflower rich limestone grassland; today it has dwindled to only 1.5 percent. The grasslands are home to more than 100 species of wildflowers and grasses and 25 species of butterflies. Numerous rare plants, including many species of orchid plus the pasque flower and Cotswold penny cress, are found here, along with several species of nationally rare butterflies.
When: Spring through early fall.
Info: cotswoldsaonb.org.uk; escapetothecotswolds.org.uk
Why: A whopping 12,000 wildflower species have been recorded throughout the state of Western Australia, with a five-month blooming season and a host of tourism services developed specifically to track down the biggest or most colorful display as well as the rarest or most unusual species.
When: From July in the warmer parts of the state through November in the south.
In particular: The southwestern region boasts more species of flowering plants than almost anywhere else in the world. Stirling Range National Park has 1,500 species, including more than 100 orchid species and 80 endemic species, most famously its mountain bells. Nearby Banksia Farms botanical gardens is home to the annual Celebration of Mount Barker Wildflowers (Sept. 1 to Oct. 30, wildflowerswa.com) Other wildflower hot spots: Lesueur National Park, with more than 820 species, including 123 orchid species, and many plants found nowhere else in the world; and the Margaret River region, the extreme southern corner of the state, where you'll find three-quarters of the state's 12,000 species of wildflowers, from orchids to arum lily and kangaroo paw. Near Perth, the state capital, Kings Park and Botanic Garden is home to the long-running Kings Park Wildflower Festival, which has grown from a weekend to a monthlong celebration every September. (bgpa.wa.gov.au/kings-park)
Info: westernaustralia.com; mountbarkertourismwa.com.au (for Stirling Range), margaretriver.com; and dec.wa.gov.au/index.php (the Department of Environment and Conservation of Western Australia, which has information on all the parks and natural areas).
NATIONAL WILDFLOWER WEEK
When: May 7 to 13 (National Public Gardens Day is May 11).
What: Events throughout the week highlight wildflowers' beauty and promote their value: conserving water, providing habitat for birds, butterflies and other wildlife; and protecting the soil from erosion. Native plants also usually require less maintenance than non-native species.
Info: The headquarters for the event is the Ladybird Johnson Wildflower Center in Austin, Texas. To find events in a particular area, check the National Organizations Directory (wildflower.org/organizations/) for local contacts.