Manna ash is a decidious tree and native to southern Europe and southwestern Asia. Throughout Exeter (UK) it is planted as an ornamental tree as well as a street tree. When given the right conditions it can grow between 15 to 25m with a trunk diameter of up to 1m. As a street tree it typically grows much small smaller - probably up to 10m. It is quite slow growing in comparison to other members of the Ash family. For Manna ash to thrive it requires full sunlight. When in flower it really stands out and they are pollinated by insects as well as the wind. The flowers are fragant and for some people the smell can be quite overwhelming.
Overall it is considered a 'medium' sized tree. Sometimes they are grafted onto the rootstocks of Fraxinus excelsior (Common ash) and when this happens the graft line is quite conspicuous. Althought it is typically known as Manna ash the other common name is South European flowering ash. Manna ash is able to tolerate air / car pollution which is why it is sometimes planted as a street tree.
The leaves are in opposite pairs, pinnate, 20–30 cm long, with 5 to 9 leaflets
They make suitable street trees as they can tolerate traffic pollution
The leaves are in opposite pairs, pinnate, 20–30 cm long, with 5 to 9 leaflets. The leaflets are broad and ovoid in shape which helps with identification as Common ash and Weeping ash are very different. Each leaflet is around 5-10cm in length and usually round 2.5cm-5cm in width. The leaflets are finely serrated with wavy margin also have a slight point at the end. The underneath of the leaves have small hairs between the veins. The autumn colour is variable with a mix of yellows and purples.
The creamy white flowers really stand out
The light brown buds are fuzzy to the touch
The flowers of Manna ash are very showy compared to most other members of the Ash family and are usually in full flower in April / May. It is dioecious meaning that the trees are either all male or all female and both must be planted nearby to allow for fertile seeds to be made. The flowers are produced in dense panicles around 10–20 cm long. Each individual flower has four slender creamy white petals which are very small (around 5–6 mm). The female flowers change into samaras and they start off a light green colour and eventually turn light brown and become very papery to the touch. The seeds (samaras) are dispersed by the wind and grow quite readily in the surrounding areas.
The autumn canopy is very pretty with a mix of yellow and purple leaves
The bark is smooth and grey in both young and older trees
The bark of Manna ash is smooth and grey in colour in both young and old trees which helps with identification. The buds are the same shape as Common ash but the colour is light brown rather than charcoal black. The buds are covered in short hairs giving it a fuzzy touch. In the UK it is planted only for ornamental purposes but it does have other uses in different countries. A sugary substance known as 'Manna' can be harvested from the tree from as little as 10 years old. Both Mannrose and Mannitol are products that can be made from the sugary sap of Manna ash.