Late Summer Insect-Friendly Perennials

For many of us the high spot in almost every garden is that time in late June when just about everything seems to be in full flower and the garden is humming with insects.  As the summer moves on, there can be a lack of colour, and good, late-flowering varieties of insect-friendly plants are less easy to find than those that burst into bloom in June and July.  This can all add up to a lack of pollen and nectar for our garden insects from August onwards, just when it is most needed. Unless you include annual bedding plants in your herbaceous borders, the result can be a late summer garden dominated by foliage.

Maintaining colour in the garden ‘all year round’ is something that plenty has been written about, but delightful as striking bark or colourful foliage can be, these features do nothing to help our native insects. These attributes can make a garden look considerably more attractive when the flowers have faded, but won’t enhance the wildlife value of your plot at all.  As we move into the month of August, we need to boost the natural food that native insects such as honey bees, bumblebees, butterflies and moths require, before the day length begins to shorten considerably and the weather starts to get cooler. These are the natural occurrences that trigger preparation for hibernation.  In fact some insects including the little red mason bee have already completed their life cycles and are resting in their pupal stage until next spring.  August is the month when more species of butterfly are visible in gardens than at any other time of year and to take advantage of this fact we need to plant our borders and pots accordingly. 

Buddleia is a good choice for many of the August butterfly species but in smaller gardens, or where there are narrow borders, we may want the versatility and changing interest of herbaceous plants. Peacock, small tortoiseshell, brimstone and painted lady are on the wing this month.  These particular species all need to top up their energy reserves before hibernation or migration begins in September.  Painted lady butterflies start to make the long journey south across the Continent next month and only those with sufficient energy reserves and a good helping of luck will actually make it.  So what can we plant to enhance the garden at this time, both for ourselves and the wildlife we have around?  The answer could be some of the beautiful old-fashioned cottage garden plants that provide nectar for these insects this month, and luckily the majority of them are easy to grow. 

Many of these later flowering perennials have more vibrant colours than early summer flowers – bright yellows, reds and pinks.  Top on my list at this time for their wildlife attracting potential are the daisies or Compositae, especially favourites such as Echinacea, Rudbeckia and the Michaelmas daisies.  This versatile family is huge and includes wildflowers as well as good wildlife-friendly garden plants for many different situations. Echinacea or coneflower is now well known for its herbal properties.  A native of North America, its large bright pinky-purple flowers are set off by the central dark brown ‘cone’.  It is a handsome plant for any garden, with the advantage of stout stems that rarely break in windy weather.  In a sunny spot, these large flowers attract masses of honeybees and bumblebees, as well as the butterfly species that are around at this time in the summer. White varieties of this plant are available, but to my eye lack the impact of the true species, Echinacea purpurea or its pink varieties.

The perennial Rudbeckia is similar in form and shape to the coneflowers, but comes in even more vibrant colours.  Often known as ‘Black-eyed Susan’ the varieties of this plant have bright yellow or orange petals.  As the summer wears on, the petals droop to expose the black central cone that gives the plant its common name.  Again these are good bee and butterfly plants and are versatile in their requirements.  Almost any good soil will accommodate them as long as they are in full sun.

Many species of bee and bumblebee are especially busy at this time of year.  Both the workers and young queen bumblebees are busy foraging for pollen and nectar, and taking it back to the nest which is generally hidden away in the ground in amongst long grass, sometimes on a sloping bank.  The young queens will need to build up energy stores to allow them to hibernate through the winter to begin new bumblebee colonies in the spring next year.   There are many varieties of Echinacea and Rudbeckia available and these are excellent nectar providers, but for their pollen requirements bees must look elsewhere.  This is where the Michaelmas daisies - a large group of plants - come into their own.  There are several different species and many varieties, not all of which will attract wildlife, so they must be chosen carefully. Perhaps the answer is to beg from a friend a cutting of anything that seems to attract bees and butterflies in their garden, rather than take a chance on a Garden Centre plant, however pretty.   

One quite early flowering Michaelmas Daisy always performs in this respect. Aster x frikartii flowers over a long period, has delicate pale mauve flowers on branching stems and is relatively short in stature, making it ideal for the smaller garden.  My favourite Michaelmas Daisy though is a tall, un-named pink variety that came from a friend.  It starts to flower later this month and continues into October, the leaves are always covered in mildew and it spreads to the point of getting out of hand, but its ability to attract red admiral butterflies is unsurpassed. It is one of perhaps five plants in my garden that I would never be without.

The colourful list for this time of year goes on and on.  As well as the daisies there are many varieties of purple loosestrife, in particular Rosy Gem, the Echinops or Globe Thistles, Anchusa, Japanese Anemone and even the old fashioned hollyhock that will all continue to provide food for many species of insect right through to the end of the summer.  But we shouldn’t forget a couple of the best and easiest to grow wildflowers that are valuable now.  The field scabious and greater knapweed will happily adapt to a border, or will thrive in their true element amongst native grasses in a meadow area.  And they have the advantage of encouraging species of butterfly such as meadow brown and marbled white that may not visit other garden flowers. 

August is a good time to take a critical look at borders and plan to boost the colour for next year.  By adding more perennial plants in late autumn we can prolong the summer season for ourselves and the insects that visit us. All these easy to grow plants need is a sunny spot, a good organic mulch in early spring and they will fill the garden with colour through August, into September and beyond.

© Text and photographs Jenny Steel 2017