Grasses asserting themselves in my late summer garden

To work with grasses you need to know that they tend to fall into two groups: warm season and cold season grasses, plus maybe a few that don’t fit conveniently into these artificial groups.

Molinia caeruleaMolinia caerulea subsp. caerulea ”Poul Petersen’

The  group we refer to as warm season grasses contains some of the most exciting and commonly grown ornamentals. Such grasses need heat to trigger them into growth and in a temperate climate such as in the Netherlands and England they spend the first half of the year as low, ground-covering clumps.

Miscanthus sinensis 'Punktchen'Miscanthus sinensis ‘Punktchen’

Eventually temperatures rise and so do these grasses at a speed that imparts a tangible dynamic to our gardens in late summer. Well finally, following our cold spring and summer it has started to happen in my trial gardens here in Amsterdam.

Miscanthus sinensisMiscanthus sinensis ‘Hermann Mussel’ is one of the fastest growing cultivars; I need to reduce the size of its clump every second year – or at least I should do.

In early summer my garden was low, colourful and pleasingly under control. In the last two weeks all of that has changed.

CrocosmiaThe colour pallet has moved from soft violet blue tints to smoldering oranges and perky yellows and although the warm season grasses have yet to come into flower, their foliage is rising skywards and pulling the garden with it.

Late summer naturalistic perennial bordersCool season grasses have already played their part in the garden’s choreography. These grasses grow during the cool of autumn and spring, flowering in early summer and becoming dormant with the onset of  the heat of summer. This year many have continued to contribute to the garden for far longer as temperatures, up until two weeks ago, have been unusually low.

Melica uniflora 'Alba'Melica uniflora ‘Alba’ a typical cool season grass, still looking good this year in August.

The exception to this is my beloved Calamarostis x acutiflora which forms upright stands of flower spikes before the end of June. By now these grasses are dormant but their silhouettes remain effective all summer and on into winter.

Calamagrostis x aculifloraCalamagrostis x aculiflora ‘Overdam’ forms a hedge that divides this part of the garden.

The real fireworks will begin fairly shortly when warm-season miscanthus, panicum and pennisetum grasses start flowering, but already they are strongly influencing the garden’s mood and controlling the spatial relationships within it. Together with the collumns and walls formed by the calamagrostis, a wild and overwhelming landscape is rapidly reaching a crescendo.

Miscanthus grasses with rudbeckia and helenium flowers Miscanthus sinensis ‘Ghana’ with heleniums and rudbeckias.