On a hot summer day, cool blue is a refreshing colour for the garden and during these recent weeks of warm, dry weather, several blue-flowering plants in my garden have been delivering standout performances.
When it comes to using blue in the garden, combine it with white flowers and silver-leafed plants for a harmonious effect that is calming, soothing and relaxing.
From a design perspective, another interesting quality of blue flowers is that they seem to recede from us. This can be used to increase the sense of spaciousness in your garden. If you have a small or cramped area, using blue with other cool colours will make that space feel larger than it is.
Blue-flowering plants also work well as focal points and can make striking contrasts with the yellows, oranges and reds of plants like kniphofia, crocosmia and monarda.
Just now, one of the most prolific blue flowers in my garden is a group of Agapanthus ‘Navy Blue’ that sits at the front of a south-facing border where they are baked in full sun.
Otherwise known as African lily, this is the ideal location in a well-drained soil and they are clearly revelling in it. While the name ‘Navy Blue’ might not be considered particularly original in the context of plant names, this is a superb variety bearing deep navy-blue flower buds that open into large heads of rich blue, trumpet-shaped blooms with darker, violet stripes down the centre of the petals.
The globe-like clusters of flowers are held high on tall, leafless stems above compact clumps of narrow leaves and the seedpods that follow are almost as attractive as the flowers. It is a deciduous variety and, in general, deciduous agapanthus tend to be longer flowering and hardier than evergreen types.
Nearby, in the same border, the first flush of flowers on the uniquely coloured Rosa ‘Rhapsody in Blue’ has just finished. Its sweetly scented, semi-double blooms are purplish-blue fading to slate-blue.
Repeat blooming
To encourage repeat blooming and a second flush of flowers in a few weeks’ time, I have cut each faded flower head, and the stem beneath it, back to the first outward-facing leaf with five leaflets.
One of the best blue-flowering phloxes in flower now is Phlox paniculata ‘Blue Paradise’. It features domed clusters of violet-blue flowers which make a very striking pairing with vivid orange crocosmias.
Problems with mildew
To prevent problems with mildew on phlox, ensure good air circulation around the plants and maintain adequate and consistent soil moisture around the root area using a layer of mulch and applying water at the roots as necessary.
Hardy geraniums also offer a variety of blue shades, blooming profusely in spring and summer. A champion among the many hundreds of hardy geranium cultivars, Geranium ‘Rozanne’ will lift a border frontage with clouds of iridescent blue flowers from June until frost. Another long-blooming favourite of mine is Geranium wallichianum ‘Havana Blues’ with large, saucer-shaped, lavender blue flowers, each adorned with prominent dark blue veins and a white central zone.
Commonly known as sea hollies, eryngiums have unique, thistle-like flowers with spiny bracts in a range of metallic blues. Drought-resistant, they are perfect for sunny, well-drained spots and coastal gardens. Making a magnificent statement in several of our borders this year is Eryngium x zabelii ‘Big Blue’. Its stiff, branched stems are topped with shimmering, electric blue flowers over a mound of deeply-divided, silvery-green foliage.
Bold statements
Equally impressive are the bristly, golfball-sized flower heads of globe thistles or echinops. These make a bold statement at the top of tall stems clothed with coarse, thistle-like leaves that look more menacing than they really are.
One of the best blues is Echinops ritro ‘Veitch’s Blue’ featuring long-lasting, steel-blue spheres of spiky buds that open into globular heads of tiny, dark blue flowers. Growing up to 1.5 metres high, globe thistles make good cut flowers and are highly attractive to bees, butterflies and other pollinating insects.
Pollinators are also attracted to the blue flowers of catmints and Nepeta x faassenii ‘Purrsian Blue’ is one I highly recommend for its compact stature and deepest blue flowers.
By mid-July, its main blooming period is usually complete but pruning it around this time will encourage further flowering and maintain a neat appearance.
Some nepetas, like ‘Walker’s Low’, can become leggy and floppy and with these, I cut the stems back to just above where new growth is visible emerging from the base of the plant.
With ‘Purrsian Blue’, I simply use a hedging shears to cut off all the flowerheads to just above the first leaf and await a welcome phase of new flowers.
Mary Keenan and Ross Doyle run Gash Gardens, Co Laois. See gashgardens.ie.
Q&A: Why are rose buds not opening?
Rose bloom balling.
Why are some of the flower buds on my roses not opening and rotting? – Nuala, Donegal.
This problem is known as ‘balling’ whereby fully-developed flower buds fail to open properly, often turning brown and rotting before they can bloom. It occurs in heavily petalled double flowers, most notably roses and peonies. Wet weather saturates the outer petals and subsequent hot sunshine dries and fuses them, preventing the bud from opening.
This can sometimes be remedied by removing the outer petals to release the ones underneath. Correct pruning and regular dead-heading of the faded blooms will help maintain good air circulation which is crucial to dry the buds quickly. If watering, always direct water at the base of plants rather than the foliage and flowers. Remove balled buds promptly before grey mould sets.
- Stock up: Increase your stock of favourite climbers, roses, shrubs and tender perennials by taking semi-ripe cuttings which should root easily at this time.
- Tidy: Tidy up fallen leaves and flowers from roses to discourage the spread of fungal diseases.
- Dried: To fill your house with the lovely scent of home-grown, dried lavender, cut lavender now just as the flowers start to open. Tie the cut stems into bunches and hang them upside down to dry.
- Plant: Plant autumn-flowering bulbs such as nerine, colchicum and Crocus speciosus
.
On a hot summer day, cool blue is a refreshing colour for the garden and during these recent weeks of warm, dry weather, several blue-flowering plants in my garden have been delivering standout performances.
When it comes to using blue in the garden, combine it with white flowers and silver-leafed plants for a harmonious effect that is calming, soothing and relaxing.
From a design perspective, another interesting quality of blue flowers is that they seem to recede from us. This can be used to increase the sense of spaciousness in your garden. If you have a small or cramped area, using blue with other cool colours will make that space feel larger than it is.
Blue-flowering plants also work well as focal points and can make striking contrasts with the yellows, oranges and reds of plants like kniphofia, crocosmia and monarda.
Just now, one of the most prolific blue flowers in my garden is a group of Agapanthus ‘Navy Blue’ that sits at the front of a south-facing border where they are baked in full sun.
Otherwise known as African lily, this is the ideal location in a well-drained soil and they are clearly revelling in it. While the name ‘Navy Blue’ might not be considered particularly original in the context of plant names, this is a superb variety bearing deep navy-blue flower buds that open into large heads of rich blue, trumpet-shaped blooms with darker, violet stripes down the centre of the petals.
The globe-like clusters of flowers are held high on tall, leafless stems above compact clumps of narrow leaves and the seedpods that follow are almost as attractive as the flowers. It is a deciduous variety and, in general, deciduous agapanthus tend to be longer flowering and hardier than evergreen types.
Nearby, in the same border, the first flush of flowers on the uniquely coloured Rosa ‘Rhapsody in Blue’ has just finished. Its sweetly scented, semi-double blooms are purplish-blue fading to slate-blue.
Repeat blooming
To encourage repeat blooming and a second flush of flowers in a few weeks’ time, I have cut each faded flower head, and the stem beneath it, back to the first outward-facing leaf with five leaflets.
One of the best blue-flowering phloxes in flower now is Phlox paniculata ‘Blue Paradise’. It features domed clusters of violet-blue flowers which make a very striking pairing with vivid orange crocosmias.
Problems with mildew
To prevent problems with mildew on phlox, ensure good air circulation around the plants and maintain adequate and consistent soil moisture around the root area using a layer of mulch and applying water at the roots as necessary.
Hardy geraniums also offer a variety of blue shades, blooming profusely in spring and summer. A champion among the many hundreds of hardy geranium cultivars, Geranium ‘Rozanne’ will lift a border frontage with clouds of iridescent blue flowers from June until frost. Another long-blooming favourite of mine is Geranium wallichianum ‘Havana Blues’ with large, saucer-shaped, lavender blue flowers, each adorned with prominent dark blue veins and a white central zone.
Commonly known as sea hollies, eryngiums have unique, thistle-like flowers with spiny bracts in a range of metallic blues. Drought-resistant, they are perfect for sunny, well-drained spots and coastal gardens. Making a magnificent statement in several of our borders this year is Eryngium x zabelii ‘Big Blue’. Its stiff, branched stems are topped with shimmering, electric blue flowers over a mound of deeply-divided, silvery-green foliage.
Bold statements
Equally impressive are the bristly, golfball-sized flower heads of globe thistles or echinops. These make a bold statement at the top of tall stems clothed with coarse, thistle-like leaves that look more menacing than they really are.
One of the best blues is Echinops ritro ‘Veitch’s Blue’ featuring long-lasting, steel-blue spheres of spiky buds that open into globular heads of tiny, dark blue flowers. Growing up to 1.5 metres high, globe thistles make good cut flowers and are highly attractive to bees, butterflies and other pollinating insects.
Pollinators are also attracted to the blue flowers of catmints and Nepeta x faassenii ‘Purrsian Blue’ is one I highly recommend for its compact stature and deepest blue flowers.
By mid-July, its main blooming period is usually complete but pruning it around this time will encourage further flowering and maintain a neat appearance.
Some nepetas, like ‘Walker’s Low’, can become leggy and floppy and with these, I cut the stems back to just above where new growth is visible emerging from the base of the plant.
With ‘Purrsian Blue’, I simply use a hedging shears to cut off all the flowerheads to just above the first leaf and await a welcome phase of new flowers.
Mary Keenan and Ross Doyle run Gash Gardens, Co Laois. See gashgardens.ie.
Q&A: Why are rose buds not opening?
Rose bloom balling.
Why are some of the flower buds on my roses not opening and rotting? – Nuala, Donegal.
This problem is known as ‘balling’ whereby fully-developed flower buds fail to open properly, often turning brown and rotting before they can bloom. It occurs in heavily petalled double flowers, most notably roses and peonies. Wet weather saturates the outer petals and subsequent hot sunshine dries and fuses them, preventing the bud from opening.
This can sometimes be remedied by removing the outer petals to release the ones underneath. Correct pruning and regular dead-heading of the faded blooms will help maintain good air circulation which is crucial to dry the buds quickly. If watering, always direct water at the base of plants rather than the foliage and flowers. Remove balled buds promptly before grey mould sets.
- Stock up: Increase your stock of favourite climbers, roses, shrubs and tender perennials by taking semi-ripe cuttings which should root easily at this time.
- Tidy: Tidy up fallen leaves and flowers from roses to discourage the spread of fungal diseases.
- Dried: To fill your house with the lovely scent of home-grown, dried lavender, cut lavender now just as the flowers start to open. Tie the cut stems into bunches and hang them upside down to dry.
- Plant: Plant autumn-flowering bulbs such as nerine, colchicum and Crocus speciosus
.
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