Aeonium, the tree houseleeks, is a genus of about 35 species of succulent, subtropical plants of the family Crassulaceae. Many species are popular in horticulture. The genus name comes from the ancient Greek αἰώνιος / aiōnios (ageless). While most of them are native to the Canary Islands, some are found in Madeira, Cape Verde, Morocco, in East Africa (Ethiopia, Somalia, Uganda, Tanzania and Kenya) and Yemen.

Description

The succulent leaves are typically arranged on a basal stem, in a dense, spreading rosette. A feature which distinguishes this genus from many of its relatives is the manner in which the flowers bear free petals, and are divided into 6 or 12 sections. With the exception of Aeonium simsii, each rosette produces a central inflorescence only once, and then dies back (though it will usually branch or offset to produce ensuing rosettes).

Low-growing Aeonium species are A. tabuliforme and A. smithii; large species include A. arboreum and A. valverdense. They are related to the genera Sempervivum, Aichryson and Monanthes, as can be seen by their similar flower and inflorescences. Recently,[when?] the genus Greenovia has been placed within Aeonium.[citation needed]

Species and distribution

All but two species are native to at least one of three different Macaronesian archipelagos (the Canary Islands, Madeira, or Cape Verde). Most aeoniums are from the Canary Islands, The only species not native to these three Macaronesian island groups (Aeonium stuessyi and Aeonium leucoblepharum) are found in Ethiopia, Kenya and Tanzania; and Ethiopia, Kenya, Sudan, Uganda and Yemen, respectively. Aeonium arboreum is native to both the Canary Islands and Morocco.

Species accepted by Plants of the World Online as of April 2023:

SpeciesDistribution
Aeonium aizoon (Bolle) T.H.M.MesCanary Islands (Tenerife)
Aeonium appendiculatum BañaresCanary Islands (La Gomera)
Aeonium arboreum (L.) Webb & Berthel.Canary Islands (Gran Canaria, Tenerife, La Gomera, La Palma, El Hierro); Morocco
Aeonium aureum (C.Sm. ex Hornem.) T.H.M.MesCanary Islands (Gran Canaria, Tenerife)
Aeonium balsamiferum Webb & Berthel.Canary Islands (Lanzarote, Fuerteventura)
Aeonium canariense (L.) Webb & Berthel.Canary Islands (Gran Canaria, Tenerife; La Gomera, La Palma, El Hierro)
Aeonium castello-paivae BolleCanary Islands (La Gomera)
Aeonium ciliatum (Willd.) Webb & Berthel.Canary Islands (Tenerife)
Aeonium cuneatum Webb & Berthel.Canary Islands (Tenerife)
Aeonium davidbramwelii H.Y.LiuCanary Islands (La Palma)
Aeonium decorum Webb ex BolleCanary Islands (Tenerife, La Gomera)
Aeonium dodrantale (Willd.) T.H.M.MesCanary Islands (Tenerife)
Aeonium glandulosum (Aiton) Webb & Berthel.Maderia (Madeira, Desertas, Porto Santo)
Aeonium glutinosum (Aiton) Webb & Berthel.Madeira (Madeira, Desertas)
Aeonium gomerense (Praeger) PraegerCanary Islands (La Gomera)
Aeonium goochiae (Christ.) PraegerCanary Islands (La Palma)
Aeonium gorgoneum J. A. SchmidtCabo Verde (Santo Antão, São Nicolau, São Vicente)
Aeonium haworthii (Salm-Dyck ex Webb & Berthel.) Webb & Berthel.Canary Islands (Tenerife)
Aeonium hierrense (R. P. Murray) Pit. & Proust.Canary Islands (La Palma, El Hierro)
Aeonium lancerottense (Praeger) PraegerCanary Islands (Lanzarote)
Aeonium leucoblepharum Webb ex A. RichardYemen, Ethiopia, Sudan, Kenya, Uganda
Aeonium lindleyi Webb & Berthel.Canary Islands (Tenerife)
Aeonium liui ArangoCanary Islands (Tenerife)
Aeonium nobile (Praeger) PraegerCanary Islands (La Palma)
Aeonium percarneum (R. P. Murray) Pit. & Proust.Canary Islands (Gran Canaria)
Aeonium rubrolineatum Svent.Canary Islands (La Gomera)
Aeonium saundersii BolleCanary Islands (La Gomera)
Aeonium sedifolium (Webb ex Bolle) Pit. & Proust.Canary Islands (Tenerife, La Gomera, La Palma))
Aeonium simsii (Sweet) Stearn.Canary Islands (Gran Canaria)
Aeonium smithii (Sims) Webb & Berthel.Canary Islands (Tenerife)
Aeonium spathulatum (Hornem.) PraegerCanary Islands (Gran Canaria, Tenerife; La Gomera, La Palma, El Hierro)
Aeonium stuessyi H.-Y. LiuEthiopia, Kenya, Tanzania
Aeonium tabuliforme (Haw.) Webb & Berthel.Canary Islands (Tenerife)
Aeonium undulatum Webb & Berthel.Canary Islands (Gran Canaria)
Aeonium urbicum (C. Sm. ex Hornem.) Webb & Berthel.Canary Islands (Tenerife)
Aeonium valverdense (Praeger) PraegerCanary Islands (El Hierro)

Hybrids

Much hybridising has been done, resulting in several cultivars of mixed or unknown parentage. The following species and cultivars have gained the Royal Horticultural Society's Award of Garden Merit:-

  • Aeonium tabuliforme
  • Aeonium haworthii
  • Aeonium haworthii 'Variegatum'
  • Aeonium 'Blushing Beauty'
  • Aeonium 'Sunburst'
  • Aeonium 'Zwartkop'

Hybridising between Aeonium species or cultivars and other Crassulaeceae species or cultivars has produced intergeneric crosses:

Some species have been introduced in California.

UK national collections of aeoniums are held by Mellie Lewis at Clun in Shropshire and by Inverewe at Poolewe, Wester Ross in Scotland.

Images

  • Aeonium arboreum 'Atropurpureum'
  • Aeonium aureum
  • Aeonium castello-paivae
  • Aeonium decorum
  • Aeonium lindleyi
  • Aeonium nobile
  • Aeonium simsii
  • Aeonium smithii
  • Aeonium tabuliforme
  • Aeonium tabuliforme bearing inflorescence
  • Detail of Aeonium tabuliforme flower
  • Aeonium tabuliforme × arboreum 'Zwartkop'
  • Aeonium undulatum
  • Aeonium valverdense
  • R. Nyffeler, "Aeonium", in Urs Eggli, ed. Illustrated Handbook of Succulent Plants: Crassulaceae (Springer, 2003) ISBN 3-540-41965-9
  • M. Cristini, "The Genus Aeonium" (Rome, 2022) ISBN 978-88-901345-6-2