They have been part of gardens for countless generations and loved by both new and well-seasoned gardeners alike. Although we affectionately refer to them as Geraniums, they are in fact Pelargoniums and although related, are not to be confused for the hardy groundcover “true” geraniums or “Cranes bills” more commonly seen in temperate climates.
Those new to gardening often regard Pelargoniums (or geraniums) as ‘Granny plants’ or ‘Old fashioned’ and something that they recall seeing in their grandparents garden. They are easily overlooked for their amazing ability to bring wonderful colour and life to a garden, no matter its size restrictions.
Pelargoniums are easy to grow and are often etched into the memory of those who grew them as children simply from cuttings or ‘slips’ as our grandparents used to call them.
In the meaning of flowers, the pelargonium (or geranium) is regarded as the flower of friendship and makes the perfect choice as gifts for others, or can symbolise a lifelong friendship if planted in a special place in the garden.
Pelargoniums are varied in their appearance and are available in a wide variety of species and cultivars that can be utilized in the garden in various ways. They bring many long years of enjoyment for anyone willing to open their hearts to this very forgiving and easily grown species of plant. Here are just a few forms to consider next time you are looking for inspiration to fill that tired corner, balcony, courtyard or window box.
(Pelargonium x hortorum)
The most common forms found in gardens today would have to be the Zonal species. They form rounded small shrubs up to a metre in height and produce their flowers on upright stems of fifteen centimetres high. Flowers are formed in tight, rounded clusters of a posy–like structure and can be found in many colours including red, white, pink, orange and all deeper and lighter shades of those mentioned. Double flowering forms that resemble clusters of miniature roses can also be found along with many bi-coloured varieties. Most flower clusters of Zonal pelargoniums can reach up to twenty or more individual blooms that make up the flowering head.
Most zonal pelargoniums are distinguished by a darker band of colouration within the leaf area. There are though, some exceptions to the rule which can be a little confusing to the eye. Golden foliage and tri-colour foliage forms can sometimes to be found and although their flowering ability may not be as intense, they still make wonderfully bright additions to the garden where they can be used in lightly shaded corners.
Zonal pelargoniums are an easy and dependable choice for those beginning new gardens and are a happy and joyous sight when used at the front gate, beside pools along driveways or simply planted in terracotta pots on steps.
Although lacking the level of flamboyance as Regals and Zonal pelargoniums and not lacking perfume, the Ivy leaved pelargoniums have maintained their popularity over decades.
Their trailing habit and ivy shaped foliage make them easy and great choices for use in hanging baskets or on retaining walls where their gentle trailing habit is greatly admired. This group carries the widest array of flower colour in all shades along with the occasional variegated leaf forms and can be used in countless combinations for mixed window boxes or mixed planters.
They hold their blooms well clear of the shiny foliage and can be rapid growers in the right location. Although they will handle a full sun location during autumn, winter and spring, they prefer a little protection from the intensity of the summer sun.
Some varieties are well suited as small climbers on low fence lines where they will clothe their structure and smother themselves in multitudes of blooms.
(Pelargonium x domesticum)
For those fortunate enough to live where summers are less humid, the Regal Pelargoniums are a beautiful choice. This form has distinct star-shaped, bright green textured foliage and the flowers seem to sparkle and take centre stage when in bloom.
Coming in a delightful array of pastel colours from deep black reds, violet, purple, magenta, peach, apricot and white, the regal pelargoniums when in full bloom, resemble the delicate beauty of a rhododendron yet they are compact plants up to an average of 70cm in height.
The flowers on the ‘regal’ cultivars are often much larger than the zonal forms and have a more open or flamboyant presence with five large petals on each flower with deep markings on either two or more individual petals. Often the margins of each petal are highlighted and ruffled with clusters of up to six flowers per stem.
They look delightful when placed at the base of steps or amongst drier gravel style gardens where their foliage texture can be completely enjoyed as it contrasts well with their delicate orchid-like blooms.
How to plant pelargoniums?
All pelargoniums prefer an open, well-drained location if planted directly in the garden, yet most will still be happy if provided some light shade during the hottest part of summer.
Heavy clay soil may require some treatment prior to planting with gypsum and a little perlite to help with aeration as they all detest wet roots.
Although the gypsum will provide valuable calcium, a generous handful of dolomite will also provide added magnesium for nutrition uptake and help to sweeten the soil slightly by helping to maintain a neutral pH of the soil, which all pelargoniums enjoy.
If space is limited, then of course all pelargoniums are very happy and accommodating to be grown in pots, hanging baskets or window boxes. Be sure to use a high grade potting mix for best results as these carry slow release fertilisers and wetting agents to accommodate the full growth of your plants. Searles Premium Mix or Searles Peat 80 are excellent choices.
Want more pelargoniums?
The easiest and most reliable way of increasing your population and cultivars in the garden is by taking cuttings. Pelargoniums are one of the easiest of plants to propagate at home.
When taking a cutting simply look for well matured stems or 20cm long that are firm and are the thickness of a thin black marker pen. Remove (or cut back) the main crown of foliage and remove any smaller shoots.
Allow to dry out for a few hours in the shade. This helps the plants to callus over at the fresh cut. Simply place into a propagating mix such as Searles Propagating Mix.
Although pelargoniums are not overly demanding in their nutritional needs, they will always respond well to a light application every few months or so of a well-balanced slow release fertiliser such as Searles Robust. Ensuring all trace elements are available to pelargoniums will ensure strong flowering and healthy plants.
Watch out for…
Although seen as trouble-free plants, Pelargoniums in certain regions can suffer from two main fungal issues. Rust and botrytis (grey mould) are most often observed when moisture builds up in and around the plant either during summer (rust) or winter (mould).
Rust: It is always a good idea to occasionally check your plants from early summer (hot climates) and regularly remove the lower dead or yellowing foliage. This will greatly increase the air flow in and around the plants. Watering should be restricted to the base only and avoid the foliage (where possible). Rust is spread by microscopic spores that are greatly dispersed by water droplets and can spread from one plant to the next in rapid succession in humid conditions.
Botrytis: Also known as grey mould, this fungal issue can also be found during hot, humid weather, but is more commonly found during cooler areas or locations where the plants may not receive enough available sunlight. Often it will affect new growth, flower buds and stems on the plants where they look as though they are covered in a grey mould and then turn slimy. Remove all effected parts and (if possible) move plants to a more open, sunnier, location.
There are many organic sprays you may choose to combat both, but the quickest and easiest is to apply a spray of Searles Mancozeb Plus directly to the effected plants.
Pelargoniums are far tougher than many of us give them credit for and can handle extended periods of dryness far better than other species. So by simply watching your watering can help to alleviate these problems.