Blue Geraniums

Understanding "Blue Geraniums": Rarity and What to Expect

When seeking out 'blue geraniums', gardeners often encounter a common horticultural challenge: true blue is an exceptionally rare colour within the widely cultivated Pelargonium genus, which most people commonly refer to as geraniums. While vibrant reds, pinks, whites, and purples abound, a genuinely blue Pelargonium is virtually non-existent in typical garden centres. This rarity means that if you're specifically after blue flowers, you'll likely need to look beyond the conventional Pelargonium offerings. Understanding this distinction is the first step towards successfully achieving your desired floral colour scheme.

• True blue Pelargoniums are extremely rare.
• Most 'geraniums' found in shops are Pelargoniums.
• Focus on alternative blue-flowered plants for desired colours.
• Research 'true geraniums' (Geranium genus) for some blue options.

The plants commonly labelled as geraniums in garden centres and sold for summer bedding or containers are technically Pelargoniums. These have distinct characteristics from the Geranium genus (also called cranesbills), which, coincidentally, does offer a few species with blue or violet flowers. However, when the public asks for 'blue geraniums', they are almost invariably thinking of the zonal, ivy-leaved, or regal Pelargoniums, and these simply do not present in shades of true blue. Therefore, the quest for blue flowers that evoke a geranium-like presence necessitates exploring other plant families or the less common Geranium species.

Pelargoniums vs. True Geraniums (Cranesbills)

It is crucial to differentiate between these two genera. Pelargoniums, native to South Africa, are popular for their showy, often large blooms and are typically grown as annuals in cooler climates. They are sensitive to frost. In contrast, true Geraniums (cranesbills) are hardy perennials native to temperate regions worldwide. Many of these hardy Geraniums offer attractive foliage and flowers, some of which lean towards blues and violets. However, their flower shape and growth habit often differ significantly from the familiar bedding geranium. For instance, Geranium 'Rozanne', a popular cultivar, displays striking violet-blue flowers, but it is a spreading perennial, not a compact, upright bedding plant like many Pelargoniums.

What Influences Flower Colour in Geraniums?

Flower colour in plants is determined by genetics and pigment production. Anthocyanins are the pigments responsible for reds, purples, and blues. The specific type of anthocyanin and the pH of the plant's cells can influence the final hue. In Pelargoniums, the genetic pathways for producing the pigments that would result in true blue simply aren't present or dominant in the cultivars bred for garden use. While some Pelargoniums can exhibit purplish tones, these rarely, if ever, cross the threshold into a clear, bright blue. Any perception of 'blue' in a Pelargonium might be a deep magenta or a purplish-red that, under certain lighting conditions, might appear to have a bluish cast, but it is not a genuine blue.

Vibrant Blue Flower Alternatives to Consider

Given the rarity of blue Pelargoniums, the most effective approach to achieving blue floral displays is to consider alternative plants known for their blue blooms and potentially similar growing requirements. The world of horticulture offers a wealth of options that can bring beautiful blues to your garden beds, borders, and containers. When selecting these alternatives, consider factors like light requirements, soil preference, water needs, and mature size to ensure they integrate well into your existing garden design and provide a comparable aesthetic to what you envision from 'blue geraniums'.

→ Geraniums: Choosing and Growing Vibrant Pelargoniums

The most rewarding gardening choices often stem from embracing what nature offers abundantly, rather than pursuing the exceptionally rare.

Hardy Geraniums (Cranesbills) for Blue Hues

As mentioned, the Geranium genus itself is a fantastic source of blue flowers. These are robust, perennial plants that often thrive in similar conditions to many Pelargoniums, though they are typically hardier. Consider varieties like:

• Geranium 'Rozanne': Famous for its long flowering season and vibrant violet-blue blooms. It's a trailing variety, excellent for ground cover or spilling over edges.
• Geranium himalayense: Offers large, saucer-shaped flowers in shades of violet-blue with white centres.
• Geranium cinereum: Smaller plants with delicate, often silver-tinged foliage and pinkish-purple to bluish flowers.
• Geranium pratense (Meadow Cranesbill): Native varieties can have flowers ranging from pale blue to deep violet.

These true geraniums provide reliability and perennial presence, offering a different, yet equally beautiful, dimension of blue to your garden.

Other Blue-Flowering Garden Stars

Beyond the Geranium genus, numerous other plant families excel in producing captivating blue flowers. These can often be incorporated into mixed borders or planted en masse for a striking effect. Some excellent choices include:

Other contenders include forget-me-nots (Myosotis), borage, certain types of salvia, and delphiniums. Each offers a unique form and flowering habit, contributing a different texture and presence to the garden tapestry, all while delivering that sought-after blue.

Nasturtiums and Sweet Peas: Easy Blue-Tinged Options

For those seeking less formal, more 'wildflower' aesthetics, nasturtiums and sweet peas can offer interesting blueish tones, though pure blue is rare. Some nasturtium varieties can have deep, muted purplish-red flowers that might read as a dusky blue in certain lights. Sweet peas, particularly modern cultivars bred for their colour range, can include lovely purples and deep mauves that border on blue. Growing sweet peas, in particular, offers a delightful fragrance and requires vertical support, adding a different dimension to garden design. Consider varieties like 'Queen of the Night' for deep, moody colours. While not a true blue geranium, they bring charm and colour.

Selecting and Caring for Your Blue Alternatives

Choosing the right blue-flowered plant is only half the battle; ensuring they thrive requires understanding their specific needs. Just as you would research the optimal conditions for Pelargoniums, you must do the same for any alternative you select. This means paying close attention to soil type, watering frequency, sunlight exposure, and any specific feeding or pruning requirements. A plant placed in the correct environment is far more likely to flourish and provide the visual impact you desire.

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When planting, always amend the soil with well-rotted compost to improve drainage and nutrient content, especially for container plants.

Soil and Sunlight Requirements

Most blue-flowered plants that serve as excellent alternatives to geraniums generally prefer well-drained soil. Waterlogged conditions can lead to root rot, a common downfall for many plants. For sun-loving options like petunias and agapanthus, a minimum of six hours of direct sunlight daily is crucial for abundant flowering. Conversely, plants like hydrangeas and some hardy Geraniums (like Geranium phaeum) can tolerate or even prefer partial shade, especially in hotter climates, to prevent their foliage from scorching and to keep their blooms looking fresh.

Watering and Feeding Regimes

Watering needs vary greatly. Annuals like lobelia and petunias, especially when grown in containers, will require more frequent watering than established perennial Geraniums or drought-tolerant agapanthus. The key is to water thoroughly when the top inch or two of soil feels dry, rather than frequent shallow watering. Overwatering can be as detrimental as underwatering. Feeding regimes also differ. Many annuals benefit from a balanced liquid feed every two to four weeks throughout the growing season to maintain vigorous flowering. Hardy perennials, on the other hand, often require less feeding, with a top-dressing of compost in spring usually sufficing, unless they are particularly heavy feeders.

Pest and Disease Management

While Pelargoniums can be susceptible to issues like grey mould (Botrytis) and vine weevils, their alternatives have their own profiles. For instance, hydrangeas can sometimes suffer from powdery mildew or leaf spot if air circulation is poor. True Geraniums are generally robust but can occasionally be affected by rust or slugs. Regular inspection of your plants, ensuring good air circulation, and removing any affected foliage promptly are proactive steps that can prevent minor issues from becoming major problems. Prompt action and appropriate organic or chemical treatments, if necessary, will help keep your blue flowers looking their best.

Planting for Maximum Impact

Consider how you will use these blue alternatives to create a desired effect. For cascading colour in hanging baskets or window boxes, lobelia and trailing petunias are superb choices. To fill perennial borders with reliable blue hues, hardy Geraniums and agapanthus are excellent. For a dramatic statement, consider planting groups of hydrangeas or delphiniums. Mixing different shades of blue with complementary colours like whites, yellows, or purples can create visually stunning displays. Don't overlook foliage; plants with silver or grey leaves can beautifully accentuate blue flowers.

Combine plants with similar water and light needs in the same container or garden bed for simpler care and healthier growth.

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Considering Sunflowers for a Splash of Colour

While not blue, it's worth noting that if your overall aim is vibrant, cheerful garden colour and you're exploring options beyond specific flower types, plants like sunflowers (Helianthus annuus) offer a different, powerful visual. Although they are typically yellow, red, or orange, planting sunflower seeds can lead to impressive height and bloom size, providing a striking contrast to cooler blues. Understanding when to plant sunflower seeds is key; they thrive in full sun and well-drained soil, typically planted after the last frost. Their large, sunny faces bring a completely different energy to a garden, serving as a powerful accent when combined with blue-toned plants.

Making the Choice: Balancing Desire and Reality

The desire for 'blue geraniums' is understandable, given the popularity of their red, pink, and white counterparts. However, the horticultural reality is that true blue is a shade best sought in other plant species. By understanding the distinction between Pelargoniums and true Geraniums, and by exploring the vast array of blue-flowered plants available, you can achieve a garden filled with cool, captivating colours that are both achievable and stunningly beautiful. Embrace the alternatives and discover new favourites.

Evaluating Your Garden's Conditions

Before committing to any new plants, take a moment to assess your garden's specific microclimates. Is it a sunny, exposed spot or a shady, sheltered corner? Is the soil sandy and free-draining, or heavy clay that retains moisture? Answering these questions will help you narrow down the best-suited blue-flowered alternatives. For example, a hot, sunny patio might be perfect for petunias or agapanthus, while a moist, shaded border could be ideal for certain hydrangeas or woodland-loving hardy Geraniums.

Considering Bloom Times and Longevity

To ensure a continuous display of blue throughout the season, consider plants with different flowering times. While some annuals offer abundant blooms for several months, perennials like hardy Geraniums or hydrangeas might have more specific blooming windows. Planning your planting to include species that bloom sequentially – perhaps early summer delphiniums followed by mid-summer salvias and late-season asters – can provide a succession of blue colour. This careful selection ensures your garden remains visually engaging for as long as possible.

Complementary Planting for Blue Flowers

Blue flowers pair beautifully with a range of other colours and textures. Whites and silvers often create a serene, elegant effect, enhancing the coolness of the blue. Yellows provide a vibrant, cheerful contrast, making the blue hues pop. For a more harmonious, subdued palette, consider pairing blues with soft purples or lavenders. Consider also the foliage. Plants with dark green, silver, or variegated leaves can provide a backdrop that makes blue flowers stand out even more. Think about combining bushy plants like hydrangeas with spiky salvias or delicate, trailing lobelia for varied textures.

The Value of True Geraniums (Cranesbills)

It's worth reiterating the value of the hardy Geranium genus. These are not only beautiful but also exceptionally reliable. They are generally pest-resistant, tolerant of a range of conditions, and many re-bloom if deadheaded. Their cultural significance and variety mean that 'true geraniums' are a cornerstone for many gardeners seeking reliable colour and form. Exploring cultivars like 'Azure Rush' or 'Blueberry Pie' can offer specific shades of blue that might surprise you, providing a more authentic blue within the extended family of plants often grouped under the common 'geranium' umbrella.