How one gardener prettied up a boring driveway
Some may see a gravel garden as an unusual choice, but it is also surprisingly easy to love.
“I did little planting but allowed hardy species to naturalise ...”
Karen Mekalick
When we began developing our garden 12 years ago, we chose to keep the existing gravel driveway rather than lay concrete as is usual in town gardens, partly because of the environmental impacts of concrete.
Each kilogram of cement used would generate around 0.9kg of carbon dioxide. To concrete our 184 square metres, we would need 5000kg of cement, creating about 4500kg of carbon dioxide.
By sticking with the gravel, with its hard-packed clay and stony base, we retained the natural drainage and the ability to extend our planting beyond the bordering gardens.
Initially, I did little planting but allowed hardy species to naturalise, and observed what did well. Seeds germinate readily in the gravel but do not always do well in maturity with the hard clay base.
Keepers are the reliable self-seeding cinerarias, nemesia, cynoglossum, Lychnis coronaria, double-flowered feverfew (Tanacetum parthenium) and Verbena bonariensis in that order, for a succession of flowering from late winter to late summer.
I leave them to form a colourful natural-looking border that changes with the seasons, weeding out those I don’t want, and keeping the carriageway clear and weeded. The weed-free gravel enhances the planting.
I always leave a few self-seeded plants of the giant Geranium maderense with its soft, deeply cut leaves and spectacular flowers in the gateway, for practical and safety reasons: Our street is a busy foottraffic area, and our high fence means care needs to be taken when exiting, for walkers’ safety.
Our entrance also has a bit of a kink which is great for privacy but makes backing in or out a challenge. The soft leaves of the geranium do no damage to our cars’ paintwork as we drive through, but give an impression of restricted access, encouraging roadside parking.
They visually narrow the entrance enough to discourage all but the most determined courier drivers, many of whom struggle with backing out without damaging plants and the brick edging.
After observing what grows naturally, I have added more treasured species to provide interest and structure. Baptisia australis has been particularly rewarding.
It had been growing in a sunny border with good soil for several years but never produced more than three stems of flowers each year. After reading up on its origins, I moved half of my plant to the sunny side of the driveway and within a year was rewarded with a healthy clump of beautiful indigo-blue pea flowers.
Another success was Salvia argentea with its 40cm-wide furry silver leaves forming a huge cushion over the ground, and providing structure and a visual anchor for the tall stems of self-seeding Verbena bonariensis. This salvia is a personal favourite but it is rarely seen in garden centres, possibly because it is perceived as a biennial, literally flowering itself to death in its second year.
I remove the flower stems for the first couple of years while they establish and find they are reliably perennial after that.
Chrysocoma coma-aurea, with its fine needle leaves and masses of yellow button flowers, has also done well as a background plant and, if clipped back after flowering, is soon covered with more flowers whatever the season.
A variety of Lilium longiflorum adds later interest with its swirl of strappy leaves in early summer followed by white trumpet flowers in March and April.
A newcomer, tweedia (Oxypetalum coeruleum), with its beautiful star-shaped flowers, is in its first year in the gravel and I am hoping will also naturalise as its seed germinates easily.
Lower-growing varieties provide the layering effect. Along with annual alyssum, the purple-flowered Geranium incanum is also self-seeding and the prolific little hoop petticoat daffodils make a splash of colour in late winter.
Rhodohypoxis is gradually forming carpets of pink and white in spring and early summer. This little rhizome is promoted as drought resistant due to its ability to survive long periods without rain in its native South Africa and is usually seen growing in pots.
However, once a pot dries out, even for a short time, that is the end of the flowers. In the gravel, with the waterretentive clay base, flowering time is extended and they have room to spread.
To keep my husband (a keen forager) happy, a few alpine strawberries are also encouraged. Likewise, for the butterflies, there are a few self-seeded swan plants.
There are lots of other plants I want to try in the future, so I expect our driveway will change every year.
Overall, the gravel planting helps to create a sense of an informal country garden in an urban area and visitors often comment on how welcoming it feels We also get asked if we actually drive our cars in. We do. - NZ Gardener