Forsythia 1a Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia europaea 3 Copenhagen Bot Garden 150421 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia europaea 4 Copenhagen Bot Garden 150421 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia europaea 5 Copenhagen Bot Garden 150421 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia europaea 7 Copenhagen Bot Garden 150421 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia geraldiana 6 Lund Bot Garden 150422 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia geraldiana 7 Lund Bot Garden 150422 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia ovata 1 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia ovata 3 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia ovata 4 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia ovata 5 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia suspensa 1 Copenhagen Bot Garden 150421 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia suspensa 2 Copenhagen Bot Garden 150421 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia suspensa 3 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia suspensa 4 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia suspensa 5 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia viridissima 3 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia x intermedia 2 (cult) Kämpinge, Räng, Sk 130518 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia 1b Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia 1c Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia 1d Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia europaea 1 Bergianska, Stockholm 050513 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia europaea 2 Bergianska, Stockholm 050513 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia europaea 6 Copenhagen Bot Garden 150421 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia geraldiana 1 Lund Bot Garden 150422 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia geraldiana 2 Lund Bot Garden 150422 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia geraldiana 3 Lund Bot Garden 150422 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia geraldiana 4 Lund Bot Garden 150422 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia geraldiana 5 Lund Bot Garden 150422 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia ovata 2 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia viridissima 1 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia viridissima 2 Lund Bot Garden 150416 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).

Forsythia x intermedia 1 (cult) Kämpinge, Räng, Sk 130518 - Photo: Jan Thomas Johansson (© 2014 Jan Thomas Johansson).