Lupin, Lupinus spp., Fabaceae

June is the peak month for lupin flowers, although they don't seem to be such popular border plants as they once were. 

We have a family connection with lupin growing because in the 1920s my grandmother worked in Drayton Manor nursery, near Chichester in West Sussex, that specialised in growing Lupinus polyphyllus as a cut flower. This is a photo from the nursery catalogue, although the lady isn't my grandmother. The fields of flowers must have looked spectacular and I can remember as a child seeing feral descendants of these plants growing on the edge of gravel pits where the nursery once stood, and seeing them in Gran's garden. The sweet peppery scent of their flowers always triggers recollections of these stately blooms, with bees working their way methodically around and up each flower spike before moving on to the next.


Lupinus polyphyllus, which is naturally blue-flowered, was introduced from North America by the plant collector David Douglas in the  1820s and soon became a popular subject for the herbaceous border, which it graced until the Yorkshire gardener George Russell decided to try to produce plants with denser flower spikes in a wider range of colours.

Beginning just before the First World War, Russell grew thousands of lupins on his allotment and ruthlessly eliminated any that he thought sub-standard, favouring bi-coloured forms with closely spaced whorls of flowers on the flower spike. By the late 1930s he'd produced his famous Russell lupin strain and with the help of nurseryman James Baker propagated the best forms commercially from cuttings. The plants were a sensation at the 1937 Royal Horticuultural Society Chelsea Flower Show and Russell, at the age of 79, became famous, receiving an MBE and the RHS Veitch Memorial Medal for his efforts. He lived on until 1951, dying at the age of 94. Plant breeders do seem to live to a grand old age; perhaps it's the determination to see how seedlings from last year's cross pollinations will perform.

Russell probably intercrossed L. polyphyllus with other species (possibly with tree lupin and the annual L. nootkatensis) although we can't be sure because no pedigrees of cross pollinations were kept. It seems likely that he probably let bees do the intercrossing for him.


For anyone with space enough to grow the plants, breeding lupins can be rewarding , as the seedlings flower in the year after sowing. Crossing involves carefully emasculating the flowers while they were still in bud, by carefully opening the buds and removing the stamens before they can shed pollen and then, after a delay while the flower develops and the stigma matures, cross pollinating the stigma with pollen from another individual, or even another species which may or may not produce a viable hybrid seed. 


Lupin flowers, like most legumes, have a distinctive and instantly recognisable flower morphology, with a prominent standard petal at the top and a folded keel petal, enveloping the stamens and the stigma, that's flanked by a wing petal on either side.

You can always spot a lupin flower that has been 'tripped' by visiting bees because their weight forces down the wing petals so the pointed tip of the keel petal protrudes.

During the bee's visit the keel petal is pushed downwards so the stigma at the tip of its long style is forced up through the end of the keel, sweeping a plug of pollen from the anthers before it and onto the underside of the bee. You can see the pollen as the yellow deposit on the tip of the keel petal and on the stigma in this photograph. 


Plentiful pollen makes lupin flowers very attractive to bumblebees, so emasculated, cross pollinated flowers need to be covered to keep bees away until seed has set.

The most interesting lupin species that I've grown is this one - Lupinus mutabilis. It's an annual that comes from South America, where it's known as tarwi and is said to have been cultivated as a food crop by the Incas. It's seeds have very high levels of protein (40%+) and lipid (20%+) but from the horticultural point of view it's the colour and fragrance of the flowers that appeal. It's easy enough to grow provided you don't attempt to transplant it. It never recovers from the slightest root disturbance, so you either need to raise it in pots as a conservatory plant or sow it in the garden where you want it to flower.

Prickly pear, Opuntia macrocentra, Cactaceae

A large prickly pear cactus, like this Opuntia macrocentra that comes from the Pecos region of Texas, is a thing of beauty when in full flower - although those long sharp spines can also inflict acute pain. 

These magnificent flowers only last for a day and change colour to a more orange hue after pollination, which is apparently performed by bees. You can read an account of the pollination ecology of the plant here.

The fruits that form after pollination are edible in some species of Opuntia, notably O. ficus-indica, and marketed commercially as tunas that are popular in Mexico and occasionally appear on British supermarket shelves.

The stamens shed pollen soon after the flowers open in the morning but the stigma only becomes receptive in the afternoon and must be cross pollinated with pollen from a different individual plant before the flower will set seeds. The stamens are touch-sensitive, curling towards the stigma if you give them a gentle poke, mimicking the action of a visiting bee.

Flattened, jointed, photosynthetic stems called cladodes take over the function of leaves in prickly pears and most species defend themselves with long, sharp spines against grazing animals. These often have clusters of tiny, barbed hairs called glochids around their base and these are acutely irritating if the stick in soft flesh - like lips, for example. In a few species, like ...

...... this O.rufida the long spines are entirely replaced by vast numbers of glochids arranged in dense clusters called areoles. The glochids are ....

... easily detached and break off at the slightest touch, so gently brushing against one of these glochid-covered cladodes can be a very unpleasant experience. For a really close look at these nasty microscopic harpoons, click here.


Both species illustrated here are growing in the desert house in Durham University Botanic Garden.

Magnolia stellata, Magnoliaceae

If we had enough space in our back garden I would plant one of the large flowered, tree-sized Magnolia species or hybrids - probably M. x soulangeana - but we only have room for the Star Magnolia, M. stellata which comes from Japan and produces many fine flowers on a relatively compact plant. It's the earliest-flowering magnolia and the weather here over the last week, which has been unremittingly warm and sunny, has been kind to the 15 year-old specimen in garden. In a couple more days it will be at its best, but  four days from now temperatures are forecast to plummet, with maybe even some snow, so the current pristine display of flowers will probably suffer from some frost damage by the middle of next week and those pure white tepals will be scarred with brown patches. 

Part of the pleasure from growing this plant comes from watching the attractive furry flower buds swell, bringing a growing sense of expectation. When the bud scales part and the pink tepals begin to force their way out, you know that spring is gathering pace.......... but anticipation is tempered by the knowledge that spring can be fickle. It looks like this year's display of starry flowers will be short-lived...... but spectacular while it lasts.

Garden Seats

Long ago I promised myself that the next garden I have will be designed around the seating. Before I do anything else I'll identify the places that provide the best morning, afternoon and evening viewpoints and choose some comfortable seats where I'll be able to rest my weary limbs and admire my handiwork over a glass (or two) of wine. But generally speaking garden seating tends to be designed for looking at rather than sitting on and is often excruciatingly uncomfortable, unless you carry a pile of cushions around with you. Here are four attractive seats that are fine for a Digital Botanic Garden, but not much good for sitting on for any length of time. 

Edwardian cast iron fern seat - lovely to look at but cold and very uncomfortable...

... lichen covered bench - obviously the gardener here was always far too busy to sit down.....but the seat really adds character and maturity to a garden.... 

 .... follow the sun - wheel this one around your extensive acres in search of the best place to linger ... but not for too long on its hard wooden surfaces...

.... and a painfully intricate creation in cast iron, in a sun-trap surrounded by Caenothus and Wistaria....

Azara microphylla, Box-leaved azara, Salicaceae

For most of the year Azara microphylla isn't a very impressive plant - just a rather straggly shrub with masses of small, glossy leaves - but for a couple of weeks in spring it reveals a rather delicious attribute: a powerful aroma of chocolate. It produces clusters of small golden stamens from the beginning of March onwards and when I opened our back door this morning (which is the day of the vernal equinox - the first day of spring) I was greeted by the chocolate scent that the Azara that's trained against the wall was releasing in the early morning sun.

The precise perception of scent is a personal attribute and I know some people who find that, to them, it smells of chocolate. Scents are often closely interwoven with memory and to me the aroma is reminiscent of the smell of a brand of chocolate called Caramac that I was very partial to in my youth.


If you are a chocoholic gardener you can find information on cultivating Azara, which can become a small tree, here and you can find more photographs here. Sadly the web is useless for conveying scents but if you can locate a bar of Caramac you'll see what I mean about the aroma .....


It is a native of Chile.

Rhododendron dauricum, Ericaceae

I'm not a great fan of some of the overblown garden hybrid Rhododendrons but Rhododendron dauricum is always a welcome sight. It's an early bloomer - not surprising when you look at its natural geographical distribution, across northern Russia, China and Japan - and it has been flowering in my garden since the beginning of March.

The fact that it flowers on almost bare twigs enhances its beauty and no doubt ...

.... makes it more conspicuous to the first queen bees that emerge in spring from hibernation to collect nectar from the flowers. This Rhododendron species and many others in the genus have a particularly unusual way of dispensing pollen to visiting insects.

In many plants the anthers at the tip of the stamens simply burst open and expose all their pollen at once, but R.dauricum anthers dehisce through a small pore at the tip - which you can see clearly in the lower-most anther in this picture. The buzz of bees visiting the flowers makes the stamen filaments vibrate with a similarly high frequency, shaking pollen out of the pore a little at a time - which is an economical way of distributing the available pollen to as many bumblebee visitors as possible during the long flowering period in spring.

Congo Cockatoo, Impatiens niamniamensis,Balsaminaceae

Flowers don't come much gaudier than this - primary colours straight out of a child's paintbox. It reminds me of some of the more lurid boiled sweets I used to buy in the sweetshop on my way home from school.

Impatiens niamniamensis comes from tropical Africa, from montane regions of Cameroon, extending through central and East Africa where it's used medicinally to treat migraines and painful joints. It makes a spectacular house plant, with one significant drawback - it seems to be extremely susceptible to pests like whitefly and red spider. The only way I've been able to cultivate it for any length of time without it resembling the contents of Pandora's box is to frequently root new plants from clean cuttings.


The flower has a very long, curled nectar spur and I've found a few sources that suggest that it's pollinated by birds - bright red flowers are often associated with bird pollination.

A big specimen in full flower makes a fine spectacle, resembling a tree full of parrots. There was a time, when I set out in gardening, when I was primarily interested in species with subtle, muted colours but these days I'm increasingly drawn to flowers whose colours are so hot you could warm your hands on them; maybe it's a symptom of advancing years..........