Posted by: Sandy Steinman | March 6, 2013

Boyce Thompson Arboretum Bloom Update

Boyce Thompson Arboretum has a new flower bloom report that includes:

A colder winter is likely the reason blooms appear to be delayed this Spring – but plants here are hydrated and hearty, thanks to February rainfall! Visit this week and you'll see more than a dozen wildflowers — and you'll have a chance to learn about fascinating plants and their adaptations.

Peak color, though, is predicted towards the end of March. Local residents should visit as often as you can this spring to enjoy the evolving bloom. But if you'll make just one trip to see the Spring color – plan yours for later in March.

Color's getting stronger by the day! New flowers to seek during the week of March 8-15 include a bright patch of blue phacelia at the east end of the main trail, below Picketpost Mansion; also the first few yellow wallflower and desert anemone on the high trail. This should also be peak week for rhyolite bush (ragged rock flower).

One of the Arboretum's most interesting and endemic early-blooming native shrubs is rhyolite bush (AKA Crossosoma bigelovii, or ragged rock flower); many of those are at their peak this weekend — just in time for Saturday's debut guided wildflower walk. Look for these trailside above Ayer Lake, along the “switchbacks” below Picketpost Mansion, and also in the Queen Creek riparian corridor. Wild cucumber remains the most interesting and showy of our spring flowers: with “Jack & The Beanstalk” vines that have climbed their way as high as eight-feet through native jojoba, mesquite and other trees in locations throughout the grounds. Watch for clusters of tiny, off-white, starfish-shaped flowers on these thriving green vines.

Other flowers throughout the park include fetid marigold (yellow); wild rhubarb (green); London rocket (gold) and henbit (purple); as well as bluedicks and native Pipevine (Aristolochia watsonii) and Mormon tea (along the main trail from Ayer Lake uphill) where you'll also find Four O'Clock. Walk the short trail that leadsd behind the Palm Grove to smell the jasmine-sweet and unique perfume of berberis shrubs there.

BTA's “first of season” Aristolochia watsonii began blooming last week. This charismatic little plant is easily overlooked, but worth seeking: watch for the one that's blooming as you walk through the main trail's narrowest section: inside “the catwalk” where the trail narrows and is chain-link-fenced above queen creek (about 50-yards east of the suspension bridge). One of these unusual Pipevine flowers was open last week, and several more buds were poised to welcome little pollinators.

Here are a few other plants to watch for: miner's lettuce is growing strong along the high trail; still just seedlings,

and not flowering yet — but patches are thick and robust. And Mormon tea is flowering along the main trail from ayer lake uphill. Its worth bringing a magnifying glass (or invert your binoculars!) for a closeup look at these pine-cone-shaped flowers

See full report and photos at: Wildflowers at Boyce Thompson Arboretum


  1. Is this the arboretum located at UC Berkley?


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