If your garden has restricted space, the importance of plant choice will be paramount. You will have to pick plants that will survive the stressed environment, whilst delivering a display on more than one level.
In general, you will probably only be able to entertain a maximum of two or three feature plants on a terrace with restricted space, so plants that will give one long display or more than one season of colour or texture are worth noting. It is worthwhile to pay attention to seasonality, so that you always have something that is performing.
Amalanchier lamarkii – This small to medium sized tree has much to offer and is quite durable. Spring flower, with coloured buds, summer fruit and simply stunning autumn colour make this an educated choice for those with room for just one tree.
Acer palmatum – A favourite of many, this tree has plenty of elegant varieties with great autumn colour, which will take to the restricted root room in a container well. Somewhat temperamental in exposed areas, careful placement is needed with this plant, which you mustn’t let dry out.
Daphne odora – Dome shaped and evergreen, this is a wonderful plant in the winter as there is no plant in the garden that can compete with its perfume. Flowering in January, it can breathe life into a terrace when nothing else is performing.
Cornus alba ‘Siberica’ – To get the most out of this shrub and to keep it manageable, you have to be brutal with it. The stem colour is a real highlight in the winter, but you have to take a deep breath and cut it back to no more than 100mm (4 inches) in April, or as soon as the buds break. This generates rapid growth for the summer and luminous red stems for next winter.
Aster x frikartii ‘Mönch’ – a delightful light purple Michelmas daisy which just keeps flowering. In a small space, length of season is a huge factor and this plant beats all-comers. Flowering from early June through to Christmas if it escapes the frost
Hemerocallis – Commonly known as the Day Lily (as flowers last but one day), this is a great cultivar as it has lush grass like leaves and has many varieties that repeat flower over a couple of months. With hundreds of Cultivars to choose from, colour is not a limiting issue.
Allium – Only one recommendation here, the ornamental onion. Flowering in April, through May, the stately Allium can retain is flowers through the summer in dry form. Best of these is the football shaped flower of Allium christophii, but there are many to choose from, and they are all worth consideration.