Name: potato vine, Chilean potato tree, potato jasmine.
Botanical name: The potato comes from the Andes mountains of South America and its correct botanical name is Solanum tuberosum, the solanum that makes tubers. However, there are several others solanums that, while they do not make tubers, they do make very handsome decorative garden plants. Unlike the potato, which is a non-woody perennial, the ornamental solanums are woody plants. None of them are strongly woody, not strong enough to make even small trees, but they do make big bushes in some cases and some are quite vigorous climbers or wall plants. The potato species are contained in the potato family, the Solanaceae, and the familiar starry shape of the flower is very distinctive.
The Chilean potato tree, Solanum crispum, makes a tall scrambling bush, not strong enough to serve as a free-standing tree. Its wood is rather weak and the stems are flexible so that it is not grown as a free-standing bush, or it will simply flop over on to whatever support is available. Best grown where it will have support for its rangy, scrambling stems, the first flush is the peak but some flowers follow for a time. The best form of this plant is called ‘Glasnevin’ and is the one usually offered. It is very fast growing and ideal for decorating a fence while other more slow-growing climbers get going.
The potato vine or the potato jasmine vine, Solanum jasminoides, is so named because it has starry flowers that resemble jasmine. It is scented too.
This is a climber, unlike the potato tree which is halfway between shrub and climber, and it needs to be grown on a wall, or a fence or pergola. It is semi-evergreen, an excellent climber for late summer and autumn, often flowering right up to December. Only cold stops it flowering. The most common kind is the white-flowered ‘Album’.
Smaller plants for a pot
There are two solanums that make smallish shrubs. One, Solanum pseudocapsicum, makes a very small shrub, less than one metre. This is not hardy and is grown as a greenhouse pot plant. The plants can be put out for summer in any case and this helps the small white potato flowers to set seeds and form the bright red rounded fruits for which this plant is mostly grown, giving it the common name of Christmas cherry.
Another shrubby kind is also suitable for the greenhouse but could be used outdoors in summer. It has been known to survive a number of mild winters. Solanum rantonnetii makes a small shrub to about one metre tall, though less when grown in a pot. It carries masses of dark purple-blue flowers in summer and into autumn, flowering prolifically on the new growth as it opens. Watch out for greenflies and white flies on this and the Christmas cherry when grown as greenhouse plants.
Lavender comes into flower in June and it is not uncommon to see white frothy masses on the stems. This is known in many parts of the country as ‘cuckoo spit’, but about the only connection with the cuckoo is that it too is associated with June as it is often heard calling in that month.
The ‘cuckoo spit’ is actually a clever protective strategy by a little insect called a frog-hopper. The larval stages of this little bug hide in the foam. Open the foam to find the little frog-like insect. The foam is made of bubbles produced by the insect from plant juices.
It hides the insect from birds that might want to eat it, but it also keeps the insect’s outer skin supple by keeping it moist and the foam tastes very nasty, which keeps birds and other predators at bay.
Lavender is not the only garden plants that may play host to this insect and it is common on plants of many kinds, but it is very noticeable on lavender. If you consider it unsightly, you can simply wash it off with a jet spray of water from a hose, but you might decide to leave the frog-hopper in his cloud of wet bubbles!
Trees, shrubs and roses
Check tree lupins, birch and honeysuckle for aphids. Roses of the early kinds of climbers and ramblers are already in bloom. Continue to tie in the new shoots of climbing roses so that they will be in the correct position for training later. Check recently planted trees for water.
Fruit, vegetables and herbs
Vegetables may be in need of watering after hot dry days. Repeat sow lettuce, beetroot, white turnips and peas. Thin out and transplant vegetables that have reached suitable size. Control weeds early. Plant Savoy cabbage and other winter varieties.
It is not too late to plant up pots and containers and bedding in beds and borders. Be sure to control weeds among bedding plants after rain - these will take away from the planting if they are allowed to make growth. Water regularly and feed container plants.
Greenhouse and house plants
Make sure to water and feed all greenhouse plants well during the coming weeks to maintain vigorous growth during the longest days. Use a greenhouse shading material now if the house is likely to get too hot. Ventilate well during damp weather. Watch for pest build-up.
The growth of lawns has been something of a revelation after a cold spring. The peak of grass growth takes place during the last few weeks of May. Even now, regular mowing, even three times a fortnight, should be kept up.