Buddleja × weyeriana Hybrids

This article covers seedlings of the hybrid B. × weyeriana back-crossed with various B. davidii cultivars. In all respects their form and habit resembles B. davidii, with very little contribution from B. globosa apparent in their appearance. Back-crosses such as those covered in this article do technically retain the nothospecific epithet, so the cultivars treated here could be written directly as B. × weyeriana cultivars, but given they bear little resemblance to the original hybrid we have chosen to treat them separately.

These hybrids have the advantage of a zero or very low seed set, so are generally considered non-invasive. Conversely, some cultivars are known to produce viable pollen (C. Valin, pers. comm.). Several have become popular garden cultivars and are widely available. Generally they are large, well-branched shrubs with mid- to dark-green leaves, grey-tomentose on the undersides; they are semi-evergreen, only losing all their leaves in particularly harsh winter conditions. The inflorescences are often large and showy; although not conspicuously different in form to B. davidii, the flower panicle may display some tendency towards being more stepped, or in loose balls (significantly looser than in B. globosa). There is a residual yellow-gold pigment in the corolla of at least one cultivar, which becomes apparent only as the flowers fade. Flowering starts a week or two later than B. davidii in the summer (late July in northern Europe).

These hybrids can grow into large plants, to the proportions of a small tree, but can be pruned in spring in much the same way as B. davidii. The growing conditions are the same as B. davidii – a sunny position in well-drained, rich soil, particularly the soil should not be prone to winter waterlogging. They can be marginally less hardy than the most robust of the B. davidii cultivars, but usually will survive a down to –15ºC (pers. obs.).

Two members of the FLUTTERBY™ Series Buddlejas fall within the parameters of this article as they have B. × weyeriana ‘Honeycomb’ in their ancestry: ‘Podara #01’ (FLUTTERBY GRANDE™ VANILLA) and ‘Podaras #05’ (FLUTTERBY GRANDE™ PEACH COBBLER). These are each discussed under Buddleja FLUTTERBY™ Series.