Veronicas have perhaps been overshadowed in recent years by their showier cousins, the tall, stately Veronicastrums, but gardeners should remember that the genus provides some of the clearest, truest blues as well as a nice variety of garden plants from low-growing rockery types to tall border perennials.
The genus is a huge one, said to be the largest in the Plantaginaceae family at around 500 species. Some botanists even include hebe within the genus, which introduces some shrubs, but generally they are annuals or herbaceous perennials.
Many people will be well aware of the lawn weeds known as speedwells, but alongside these nuisance specimens there are many garden-worthy plants that are either low-growing mounds or medium-to-tall perennials in the border, producing slender spires of flowers in shades of blue, pink and white in midsummer.
The earliest to flower is the pale-blue Veronica gentianoides between May and June. The slightly shorter but nicely upright spires of V. spicata come next, in shades of pink, white or blue. V. longifolia is a fairly tall, vigorous species that suits a herbaceous border. It is known as the long-leafed speedwell because of its slender foliage and there are some excellent varieties with richer coloured flowers than the straight species, including ‘Blauriesin’.
Possibly the most popular varieties are bred from V. austriaca, particularly ‘Kapitän’ and ‘Crater Lake Blue’ Award of Garden Merit (AGM). Not the tallest plants, they provide their impact with the rich gentian blue flower colour.
The low-growing types such as V. umbrosa ‘Georgia Blue’ AGM, ‘Kapitän’ and ‘Crater Lake Blue’ form nice broad mats that cover the earth and suppress weeds. Small early-spring bulbs can be grown through them and then the veronicas take over, providing many flower spikes throughout the summer.
Veronicas enjoy an open, sunny position — they do not flower well in shady sites. They prefer well-drained, moist but not waterlogged soil, and are said to succeed on poor soil where other perennials fail.
Apply a well-balanced fertiliser in the spring, give them a tidy up and then mulch. Deadhead regularly to prolong the flowering period and trim after they have finished. Water them in dry periods and provide support for taller-growing species such as V. longifolia. Divide them every few years.
What the specialists say
Richard Bramley, owner, Farmyard Nurseries, Carmarthenshire
"Veronicas in my opinion are superb plants, although they are very variable, from rockery plants to tall herbaceous. They are undemanding and reliable, needing nothing but a sunny site in good soil. A tidy up in the spring and a good trim when they have finished flowering is advantageous to keep the border looking neat and we give ours a top dressing in March of a good well-balanced fertiliser such as Vitax Q4 or similar. The rockery ones need similar treatment.
"If you include Veronicastrum in this group then the back of the border nears completion. These are smaller-flowered tall plants that seem to bloom for ever in a similar yet not so large colour range.
"There are so many varieties that are special, especially some of the new ones. V. ‘Purpleicious’ is lovely with its amethyst-coloured plumes and a personal favourite is V. teucrium ‘Kapitän’. The blue of this one is heavenly, growing to about 30cm with numerous loose spikes of flowers during June and July — adorable."
David Ward, plant propagation manager, Beth Chatto Gardens, Essex
"Veronica are really useful, somewhat underused, border perennials. We grow traditional varieties such as V. gentianoides and V. longifolia here, but be aware there are also many good new varieties on the market. What veronicas do really well is provide that gentian blue in the garden, which contrasts so well with yellow. They also provide a nice vertical accent in a border.
"V. gentianoides is a very useful plant, flowering earliest in May and June. There are good variegated forms. V. longifolia is a classic border perennial, being slightly taller, with either blue or white flowers.
"Our best two varieties are probably the austriaca types ‘Kapitän’ and ‘Crater Lake Blue’ — both stunning gentian blues. They look amazing up against Golden Marjoram. Another useful plant for the rockery, front of border or for beneath taller plants is V. umbrosa ‘Georgia Blue’. It does run a bit but that isn’t really a problem.
"Our garden is a bit dry in some areas for some of the veronicas but we do quite well with them. My growing tips are to divide them regularly to maintain vigour and to encourage a good flowering display. Deadheading is important to prolong flowering. They are pretty problem-free but can get mildew."
Neil McCulloch, planteria manager, Well Hall Garden Centre, London
"Veronicas in full flower are highly attractive to customers because of their colourful flower spires. There are some really good new varieties on the market, many of which have plant breeder’s rights (PBR).
"Among them is a V. spicata type, ‘Royal Candles’ or ‘Glory’, which is a smaller perennial, producing dense spires whose deep-purple flowers open from the bottom, leaving a lovely contrasting green tip before they fully open.
"Others that do very well for us are V. ‘Georgia Blue’ and V. ‘Shirley Blue’. Both are low-growing plants with beautiful vivid flowers that we recommend for the edges of a bed or rockery."
Species and varieties
V. austriaca subsp. teucrium ‘Kapitän’ is an upright, bushy perennial that produces many
spires of deep gentian-blue flowers in early summer. Height and spread: 50cm.
V. austriaca ‘Ionian Skies’ has fine, lacy foliage and spikes of intense sky-blue flowers. Forms a loose clump. Height and spread: 30cm.
V. austriaca subsp. teucrium ‘Crater Lake Blue’ AGM (H6) is a highly popular variety that features intense blue flowers. It is a herbaceous perennial that forms a mound of toothed, oblong leaves. Height: 25cm.
V. austriaca subsp. teucrium ‘Royal Blue’ AGM (H6) is a very popular variety with gorgeous clear blue flowers. It is a bushy herbaceous perennial with toothed, oblong leaves. Height: 45cm.
V. gentianoides is an herbaceous perennial with erect stems, bearing pale washed out-blue flowers in early summer above a spreading rosette of bright glossy green, ovate leaves. Height: 45cm.
V. gentianoides ‘Tissington White’ is a lovely variety that produces spires of delicate white flowers, veined and lightly flushed with purplish blue, above rosettes of thick lance-shaped leaves. Height: 45cm. Spread: 60cm.
V. longifolia ‘Christa’ PBR is a strange plant with twisted flower spikes topped with a bright-green comb. Initially bred for the cut-flower industry — perhaps not for the faint-hearted. Height 80cm. Spread: 30cm.
V. prostrata AGM (H5) is a semi-evergreen perennial that forms a mat of narrowly oblong
dark-green leaves and produces short, erect racemes of pale- or deep-blue flowers. Height: 15cm.
V. prostrata ‘Spode Blue’ AGM (H5) is a prostrate perennial that forms a mat of narrow semi-evergreen leaves and produces erect racemes of small blue flowers in early summer. Height: 10cm.
V. ‘Shirley Blue’ AGM (H6) is an herbaceous perennial that produces erect stems bearing bright-blue flowers above a mat of oblong, deeply toothed leaves. Height: 25cm. Spread: 30cm.
V. spicata ‘Alba’ is a compact herbaceous perennial that forms clumps of mid-green lance-shaped leaves. Bears upright narrow spikes of white flowers on leafy stems in summer. Height and spread: 30cm.
V. spicata ‘Heidekind’ is a lovely plant that provides a long succession of spikes with raspberry-pink flowers in midsummer. A delightful edging plant. Height: 25 cm.
V. umbrosa ‘Georgia Blue’ AGM (H5) forms a low cushion plant that can give a year-round effect because it is semi-evergreen. Stems and young foliage are tinged reddish bronze. Deep-blue flowers are produced throughout the summer and intermittently into the autumn. Introduced by Roy Lancaster. Height: 10-15cm.
Thank you to Floramedia, which supplied the images for this article from its photo library