It's a rare thing for me to become rendered speechless, but for the last three days I've barely been able to string a couple of words together. The reason for this anomaly? The gobsmacking Isoplexis sceptrum – also known by its vernacular name of Madeira foxglove. As the name indicates, it's a member of the foxglove (Scrophulariaceae) family and is indigenous to the lightly-shaded woodlands on the botanically-rich Portuguese island of Madeira.
I've waited eight years for this glorious moment, witness five stately inflorescences bursting from each upright cluster of soft-haired leaves. What an adrenalin pumping moment. Each flower spike is sumptuous and resembles a compact Digitalis purpurea. But the orange-brown and yellow-streaked colourations are irresistible, coupled with a waxy, glistening hairy touch. Staring into each flower is awe-inspiring, especially as you're entranced by the heavy dark brown lattice work on the lower floral parts.
The Madeira foxglove is a drama queen and a must-have for any gardener's shopping list. Although it's frost tender, this small shrub is very easy to cultivate if you grow it in a large pot – and when its bursts forth with flowering ecstasy you'll be transported to flower power heaven.
• Tom Hart Dyke is a plant hunter, plantsman and heir to Lullingstone Castle in Kent, where he built and curates the World Garden of Plants.
