Return to John Miller's aloe garden in Oakland

Last Saturday, my friends John B, Justin, Kyle and I visited John Miller’s aloe garden in Oakland. John is the president of the Institute for Aloe Studies (IAS), a non-profit organization dedicated to the study and conservation of aloes, both in their natural habitats and ex situ in collections. The IAS propagates a large variety of aloe species, often from habitat seed, and sells them through their web site. The plants are grown in a greenhouse at the Oakland Zoo and in John’s personal garden.

Pre-Covid, the annual winter pilgrimage to John’s garden coinciding with the peak of the aloe bloom had become somewhat of a tradition. Somehow, I don’t know how, four years managed to go by since my last visit. While a few things have changed, most of the aloes I remembered fondly were still there. That’s the wonderful thing about plants, and gardens in general: They reward your initial investment of time and effort for many years to come.

John lives on a ½ acre hillside lot with sweeping views of Oakland and San Francisco Bay beyond. His aloe collection is one of the most extensive in the country and includes many rare species from countries other than South Africa (Zimbabwe, Uganda, Ethiopia, Madagascar). In Oakland, like in most Bay Area locations, winter lows rarely fall below freezing and summer highs rarely climb beyond the 90s. That’s the ideal climate for most aloes although John mentioned that summers are getting hotter than they used to be. In contrast, Davis, where I live, is colder in the winter and hotter in the summer even though it’s just a little over an hour away.

This visit wasn’t just an occasion to look at John’s aloes, it was also an opportunity to catch up. I spent more time yakking than taking photos so what you see below is more a random collection of snaps than a systematic survey of what’s growing in John’s garden. Sometimes just hanging out is more important than trying to document everything. On that note, let’s look at some of the special aloes in John’s garden.

Aloe powysiorum [Kenya] is a cliff dweller. Even in cultivation, its rosettes are tilted sideways instead of upright.

Aloe powysiorum has secund flowers, meaning they are arranged on one side of the inflorescence rather than distributed evenly on both sides

Aloe percrassa [Ethiopia, Eritrea] is as rare as it is beautiful

Aloe percrassa flowers

Aloe divaricata [Madagascar] in the front, Aloe rivieri [Yemen] behind it

Aloe sabaea [Yemen, Saudi Arabia] on the left

Unfurling fern frond spotted on the way into the back garden

Aloe speciosa [South Africa], one of several specimens in John’s garden. It’s easy to see why its common name is tilt-head aloe.

Aloe speciosa inflorescence. The flowers are probably opening right about now.

Aloe castanea [South Africa], commonly known as the cat tail aloe

Aloe castanea produces brown nectar. See note below for more information on that.

In this photo you can see how dark the nectar is

I do remember the many Aloe ferox on the hillside from previous visits, but I don’t remember the sea of blue

The blue is from Moraea polystachya, an iris relative from Southern Africa, which has naturalized in John’s back garden. John urged us to take some home (which we did) but warned us to be careful where we put them unless we wanted our own moraea meadow.

Aloe distans [South Africa] and Moraea polystachya [South Africa]

Aloe distans almost swallowed by Moraea polystachya

Dudleya pulverulenta, Aloe distans, Moraea polystachya, and Oxalis pes-caprae

Dudleya pulverulenta

More Dudleya pulverulenta (John says they reseed readily in his garden) in a sea of Oxalis pes-caprae, another exotic that has naturalized

Mostly Aloe ferox [South Africa]

Aloe ferox in a variety of colors: red, orange, yellow, even bicolor

Fasciated (crested) Aloe ferox flower

Aloe pulcherrima [Ethiopia] has a prostrate habit, hanging from cliffs on its sturdy stem

Looking north towards the house

The taller aloe is Aloe lukeana [Uganda], the smaller one in front of it is Aloe ankoberensis [Ethiopia]

Aloe ankoberensis [Ethiopia]

View north from the lower deck

Ferox land

John’s large greenhouse filled with cold-sensitive and/or rare species

Note on brown (dark) nectar:

Almost all aloes have clear nectar. The exception are six closely related species with sessile flowers (flowers without pedicels that attach directly to the stalk): A. alooides, A. barbara-jeppae, A. castanea, A. dolomitica, A. spicata, and A. vryheidensis. These produce brown nectar as a way to attract specific bird pollinators by visually signaling the nectar’s presence while deterring nectar robbers with a bitter taste. This adaptation helps ensure successful pollination and seed production by filtering out unwanted pollinators that might not do an effective job. For more information, see Johnson, S. D., Hargreaves, A. L., & Brown, M. (2006). Dark, bitter-tasting nectar functions as a filter of flower visitors in a bird-pollinated plant. Ecology, 87(11), 2709–2716 (PDF here).

Coincidentally, John Miller observed that the dark nectar produced by A. spicata and others is fluorescent under black light (see John B. Miller. Aloes with Fluorescent Nectar. Cactus and Succulent Journal 96(2):217 (2024)). Most likely, this fluorescence acts as a visual cue to help pollinators locate nectar and pollen.

Earlier posts about John’s garden:

• January 2021: John Miller’s fabulous aloe garden
• January 2020: John Miller’s aloe wonderland in Oakland
• December 2018: John Miller’s Oakland aloe garden (Institute for Aloe Studies)

© Gerhard Bock, 2025. All rights reserved. To receive all new posts by email, please subscribe here.