Speaking at a seminar at Barcham Trees, Thurman recommended several non-native but dependable species including:
- Lagerstroemia indica, the crape myrtle, as a good street tree which will tolerate temperatures down to -20°C;
- Quercus palustris, the pin or swamp oak, which despite its name will tolerate drought and is not affected by oak processionary moth;
- Cercis siliquastrum, the Judas tree, which remains compact in size;
- Ilex castaneifolia AGM, the chestnut-leaved holly, which is generally pest- and disease-free.
However he described Prunus x subhirtella 'Autumnalis' as "a poor tree in every respect", and advised using variegated and purple-leaved trees only in moderation, saying "let green be god".
The seminar brought together landscapers, developers, house builders, utility and highway engineers, architects and tree officers to hear the Trees and Design Action Group (TDAG) explain its recently published Trees in Hard Landscapes- A Guide for Delivery.
Using the example of the landscaping of the Bomber Command Memorial at London's Hyde Park Corner, in which which he was closely involved, Barrell Tree Consultancy managing director Jeremy Barrell stressed the importance of up-front collaboration between disciplines.
"Traditional team working often involves various people pulling in different directions in an attempt to become dominant," he said.
"There is very little discussion between disciplines, and you end up with a project which does not fit together quite right. A disjointed approach is a disaster."