The Aloe cultivar and species collection.

by Jason Sampson, Curator; Manie van der Shijff Botanical Gardens, University of Pretoria

The Manie van der Schijff Botanical Garden collections have their origins in 1923 and have been a valuable part of the Department of Plant and Soil Sciences and the University of Pretoria as a whole for the past 94 years. Our focus has always been on indigenous plants and the Aloe collections have waxed and waned with the passage of time and the interests of our Curators, but has always been good, with a mix of pure species and hybrids.

As a bit of back ground, the Manie van der Schijff Gardens proper are maintained and run completely separately from the rest of the grounds of the Hatfield campus, which is run by our Department of Facilities Management, but the Curators of the botanical collections do have an oversight function and a close working relationship with the maintenance managers of this and our other campus’, allowing the diversity of the collections to ever increase. This is the story of how one group of plants has thrived under a strongly focussed planting programme.

 

 Fig 1: Aloe ‘Capricorn’ in bloom behind the fountain at the “prow” of the Tukkies Administration Building.

Fig 2: Aloe arborescens ssp. mzinyathi blooming two stories up on the North face of the “dry” cremnophytic green wall of the Plant Sciences Building.

 

Aloe was, for various reasons, a neglected genus in the wider landscaping of the Campuses of the University of Pretoria when I took up the post as Curator of the Botanical Gardens in 2010. Probably the main reason for this is that the hybridisation work of both Leo Thamm (of Sunbird Aloes) and Andy de Wet (of De Wet Plant Breeders/The Aloe Farm) had yet to reach the level of popularity they now enjoy, and Aloes were seen as the proper domain of us plant nerds, not really as worthwhile landscaping objects for manicured and more formal garden development.

 

 

Fig 3: Another view of the “prow” of the Administration Building. This time with Aloe ‘Havenga’s Pride’ in the foreground.

 

 

Fig. 4: Aloe ‘Bafana’ in front of the HPC Building on Hillcrest Campus

 

The University of Pretoria is, in reality, the deep root from which these pioneering Aloe breeding efforts originally sprung, as this is the Alma Mater and workplace of the great ‘Oom At’ Koeleman himself, who started the Aloe Breeders Society in the ‘70’s and ‘80’s as a vehicle for his and others hybridisation efforts, to share knowledge and material and to register new, garden worthy cultivars.

 

 

Fig 5: Aloe ferox (white flowered) x A. thraskii flowering behind the Thuto lecture halls. This particular cross is one of mine.

 

I have always had a strong interest in the genus, and am also very aware of how truly amazing some of the South African bred hybrid cultivars are in a garden situation so it’s safe to say I have always wanted to see more of these used in and around Pretoria and as part of our collections.

Remember that selected Aloe hybrids are often better adapted to growing in standard garden conditions, are faster growing, may be more disease resistant and are selected for flower and form, outperforming (most) species when in bloom and often being a more compact package. They are also, hands down, more sustainable as they are mass produced in a nursery. While one can buy species Aloes that have been grown from seed from reputable nurseries, the depressing sight of large habitat Aloe marlothii standing in slowly desiccating ranks remains all too depressing a sight along road sides in Joburg and Pretoria, and at nurseries that should know better. Aloe hybrids also perform the same ecological function in a garden as species do in the wild (feed sunbirds and insects) and stretch the available flowering season from March to November in the Southern Hemisphere, this with a succession of cultivars flowering at different times, with occasional re-blooming cultivars outperforming even this amazing nine months of multi-coloured bloom!

Nothing changes overnight at a large institution, and we at Tukkies are extremely proud of our gardens, these new-fangled hybrid Aloes would have to prove themselves worthy of our grounds before they could become part of the accepted landscaping policy, so the initial introductions would be in the Botanical Garden proper, under my direct oversight. At the same time there were parallel developments that would also help catapult the genus’ popularity in the general consciousness of the institution.

 

 

Fig 6: Aloe ‘Peri-Peri’ flowering in front of the iconic Old Arts building on Hatfield Campus.

 

One of the mandates of the Botanical Garden is to increase collections, particularly of indigenous plant groups of potential research interest, as well as of conservation merit. The design and installation of the Cremnophyte based green walls of the new Plant Science Building in 2010 and 2011 was one such opportunity for us to introduce and grow new species, with Aloes a strong part of the composition. In this case we planted A. hardyi, A. arborescens ssp. mzinyathi, A. huntleyana as well as a cremnophytic A. arborescens form I had collected myself in the Waterberg. This was an extremely high profile project and these plants are now huge, with the A. hardyii in particular being probably the biggest members of their species in cultivation in Gauteng, and flower gorgeously in winter, visible to people both inside and outside the varsity as the building is on the boundary of the property. The landscaping surrounding the building also contains dozens of mature Aloe marlothii, while I have planted the balcony gardens with different forms of Aloe arborescens , A. pendens and Agave (amongst other succulent plants).

 

Fig 7: The “dry wall” of the Plant Sciences Building two years after installation. This project is extremely functional as it is an insullation layer to this section of the buidling, which was designed as a “green” project. It is also an artificial cliff face habitat.

 

 

Fig 8: Flower close up of Aloe arborescens ssp. mzinyathi.

 

 Fig 9 & 10: Gorgeous specimens of Aloe hardyii. They truly thrive on these North and Western walls.

 

At about the same time, we were gifted two 98 plug trays of Aloe ‘Peri-Peri’ from the Aloe Farm. This cultivar had recently been released but had proved less popular than the earlier ‘Hedgehog’ as it was a similar plant and the gardening public had not really caught on to how useful these small, clumping Aloes could be in a landscape. I gratefully accepted these and planted them directly in front of the Facilities Management building where they were in full and glorious bloom within a season. Incidentally, this small and free flowering plant is virtually bulletproof and without vice. It also has a close to three month flowering season in autumn and early winter.

 

Fig 11: The very first planting of a hybrid Aloe on the Hatfield campus. This bed is still in existence.

 

 

Fig 12: There are literally thousands of Aloe ‘Peri-Peri’ planted on all the Tukkies campuses, this particular bed, next to the Chapel on Hatfield campus, is particularly showy and often photographed in bloom.

 

At the end of 2011, the Aloe plantings within the Botanical Garden had begun to attract a bit of attention and we were asked to provide material for a succulent garden behind the Law building, which would become our Aloe cultivar testing area, while the grounds of the Onderstepoort campus were extensively xeriscaped, the Aloe species list provided by the Botanical Garden.

 

 

Fig 13: Part of the xeriscape behind the Law Building. Aloe marlothii ‘Polokwane form’, A. arborescens ‘Limelight’ and Aloe ‘Peri-Peri’ are shown.

 

After that it was only a matter of time before Aloe plantings began to increase, as this is a genus that talks for itself, particularly in winter! Noticeable developments in the series was the replacement of the rose garden around our Administration Building with Aloes, cycads and Agapanthus, the plants chosen to reflect our institutional colours, a water wise garden that has won us two Silver SALI awards and a re-nomination for 2018, and the development of the “Sunbird Lane” on our Sports Campus, where we have thousands of Aloe specimens of all sizes planted for public enjoyment. These plants are selectively labelled.

 

Fig 14: The xeriscape around the Administration building soon after planting at the end of 2015.

 

Fig 15: The same xeriscape in June/July 2017.

 

Fig 16: Sunbird Lane (Sports Campus) in development in July/August 2015.

 

Fig 17: Sunbird lane in July/August 2018.

 

All of our campuses now feature Aloes somewhere in the landscaping menu, with Tukkies being the proud owner of thousands, possibly tens of thousands of Aloes, and these plantings are expected to increase in future with the pressure always mounting on our water reserves. This is a fantastic flagship genus for xeriscaping, and the range of desirable plant cultivars being produced by plant breeders is ever increasing.

The trick to getting them to really work in a landscape is proper species/cultivar selection and the choice of companion plants. This genus is strongly associated with cycads, other succulent plants such as Agave and Crassula and indigenous groundcovers and shrubs such as Agapanthus, Dietes and Plectranthus within our planting palettes, and many cultivars are suited for mass planting in more formal landscapes, although I test this assumption first and issue an “approved Aloe list” with guidelines for use every year in regard to new landscape developments and upgrades.

 

Fig 18: A sight to gladden the heart: Aloe ‘Capricorn’ framing the lower entrance to the Administration building with colour.

 

The wider use of both species and hybrids in the genus has added a huge amount of value to our institutional landscapes, and winter in Pretoria is certainly a much more colourful affair nowadays!

We are also actively propagating pure species of Aloe for sale at our Cycad and Indigenous Plant nursery through the work of our Curator of the Cycad Collection, Arnold Frisby, and encourage their use alongside the (usually but not always) flashier hybrids.

 

 Fig 19: Aloe ‘Havenga’s Pride’ en masse and in full bloom at the Administration Building Xeriscape.

 

Fig 20: A weakly bicoloured A. marlothii sets off the stonework in season!

 

You can see Aloes in their glory on all our Campuses from about Mid-March to November. We have re-blooming cultivars planted around the Administration Building so one can expect to see flowers there at any time of the year, although the Agapanthus takes the show in summer.

Our Sports Campus holds the single biggest concentration of different cultivars and species with the Sunbird Lane being at its absolute best in June-July.

We also have thousands of Aloes planted around the Aula lawn in front of the Old Arts Building, these are chiefly smaller types such as Aloe ‘Peri-Peri’ mixed with young cycads, but really, there are few places one can move at the University without seeing them.

Since Aloe hybrids are bred for the home gardener’s enjoyment they are easy enough to grow in rich, well-drained soil in full sun. Most types also do well in containers.

This has been a ten year journey, and it would have not been possible without the strong team we field when talk of the landscapes of the University is made. Mention must be made of Aubrey Matthews, Francinah Mphaka, Jaqcues Smit and Johan Britz of Facilities Management, Neal Dunstan who until recently was also part of the Facilities team,  Prof. Marion Meyer and Prof. Braam van Wyk of the Department of Plant and Soil Sciences as well as the staff and students of our Institution who’s favourable notice and enjoyment of the changes to the gardens help drive the water wise planting program.

A version of this content appeared in Aloe Magazine in 2018 under the title "Aloes as ambassadors for water wise gardening at the University of Pretoria, 2010 to present." ALOE 54:1:2018. ISSN 0002-6301

Please also download and view the Virtual Aloe Walk 2020, a companion video to this article.