Pelargoniums were Michael Loftus’s earliest love. His mother, Prue, was a great collector and the uniques and scented leaf varieties were part of his life for over 50 years. Our collection of Pelargoniums is intensely personal. We abhor the violent colours of most modern Pelargoniums and specialise in the species and scented leaf varieties. All our Pelargoniums are raised at the nursery from cuttings by our grower Julie Nicholas and will flower from April – October. Whilst the Pelargonium is a tender perennial it can be easily overwintered and are wonderful plants for pots in the summer as they are drought tolerant and incredibly long flowering.
Woottens Pelargonium Encyclopaedia
Read on to find out more about Pelargoniums, specific scented varieties and how to grow, care and propagate them.
The Pelargonium is a genus in the higher family of Geraniaceae. This family also contains other common genus such a Geranium and Erodium, both of which we also grow on the nursery. Pelargoniums have been mistakenly called Geraniums since the turn of the century and although they are closely related they have very different requirements to what we call ‘The Hardy Geranium’ which is native to the UK and Europe.
Each genus can be distinguished by its flower petal arrangements and number of stamen.
Pelargoniums have two upper petals and 3 lower petals. Geraniums have 5 equal sized fairly symmetrical petals and Erodiums have 5 petals.
Pelargoniums originate from South Africa and a few areas in south-east Australia.
They are soundly perennial albeit classified as a tender perennial in this country and most won’t tolerate temperatures below freezing. Over the years at Woottens we’ve discovered a few species types that are more tolerant of frost then others and that all Pelargoniums will tolerate cooler temperatures if they are dry.
Our fascination with these plants is directed mainly towards their foliage which is more diverse than any other plant species known to man. Whilst some species have a delicate filigree leaf
P. trise – others have huge furry leaves scented with peppermint
P. tomentsoum – Some plants have triangular stems
P. tetragonum – and some are covered in tiny thorns
P. echinatum – As well as size and shape the foliage comes in a explosion of different fragrances – below are listed just a few with their corresponding varieties.
Great Glemham Lemon
Prince of Orange
Attar of Roses
Grey Lady Plymouth
Deerwood Lavender Lad
Pelargoniums have their own specific groups derived from years of breeding to make categorising them easier. The main groups are as follows
In 2017 we are aiming to have this section of our website as a ‘search by group’ area for Pelargoniums. Please bear with us whilst the work is carried out
Species Pelargoniums are the original plants collected from the wild. Native to South Africa they like dry conditions and hot summers. You can identify whether a plant is a wild species rather than a hybrid by its name. The second word of the name will ALL be in lower case letters and will be descriptive of that plants. For example PELARGONIUM tomentosum is a natural form and the word in Latin means ‘downy’ or soft leaf.
All species plants must be kept on the dry side in the winter. Woottens we have found many of the species plants more tolerant to cold spells and some have survived temperatures to -5 degrees if kept dry. Although allowing the plants to drop to these temperatures is not recommended. If it does happen don’t automatically dispose of the plants as it may still survive. In a hot summer these plants will go to seed which can be collected and sown and in the right conditions young plants will grow true to form.
Pelargoniums have many uses, apart from the traditional place on the windowsill. The Victorians liked to bank the scented leafed varieties on tiered staging inside glassed porches. People entering & leaving the house would brush against them, thereby releasing their scent. A pleasing salutation! Some leaves are used in cooking or for making oils, and a customer once told us that the leaves of P. Queen of Lemons is a wonderful addition to a gin and tonic on a summers afternoon! Scented leaf varieties vary hugely like the species plants they were derived from, again they are more tolerant of cooler temperatures than the blousey regal group but they are more prone to aphid attacks. Regular soap sprays will keep the bugs at bay and for those usually housed in a glasshouse a few weeks in the open air will eradicate any infestations Pelargonium Queen of Lemons
These are the flamboyant relatives of the other groups – with the largest flowers that are a far cry away from the delicate 5 petalled form of the true Pelargonium. The petals are wide and often ruffled, they make a wonderful show in pots in the summer time and most have a neat compact foliage structure. They all have very similar large cabbage like leaves and thick stems. In this group we find some of the darkest flowers available, P. Minstrel Boy has almost black flowers and P. Gwendolin is a deep wine red. Breeding this group with scented leaf varieties has led to some truly exquisite hybrids including P.Copthorne and P.Ashby. Known as scented regals. This particular group requires regular deadheading to keep up appearances.
Bred by the Victorians for their height, the decoratives grow between 40-60cm and are much more erect than the regals. They have smaller neater flowers that have 5 rounded lobes and are often bicolours. Meaning the top two petals are a different colour to the bottom three – P.Vicki is a prime example. These plants are perfect for floriferous pot displays and are as exquisite as the regal varieties. Decorative Pelargoniums benefit from a hard cut back on a warm sunny day in September to prevent soft leggy growth causing them problems in the winter.
This group contains some of the largest growing varieties in the UK. P. Purple Unique can grow up to 3metres tall in a glasshouse or conservatory and has huge green leaves. Most uniques are scented and have large yet elegant flowers. One of the best cultivars ever bred belongs to this group – P.Voodoo – a highly floriferous plant displaying bright red flowers with a black centre. Voodoo remains undamaged by heavy rainfall or wind and therefore is ideal for large pot displays outside all summer.
Possibly the most common Pelargoniums on the market today, Ivy leaf varieties have the distinctive thick succulent leaves shaped like the native Hedera or Ivy. Due to their trailing habit they are often used in hanging baskets. Their succulent properties mean they can be left very dry without suffering and therefore are relatively robust in the winter. They have long petals normally in shades of red, pink or white. Some have beautifully mottled foliage like P. Rollers Pioneer commonly known as the Crocodile Pelargonium due to it’s leaf pattern.
Miniature or dwarf forms with petite flowers and small leafed foliage. The plants themselves will eventually grow to 60cm high and wide albeit slowly. Often used in shows due to the carpet of flowers each plant can produce. Lightly scented foliage. A dainty and neat group of Pelargoniums that severely dislike overhead watering. Feeding fortnightly through the growing season will encourage the blankets of tiny flowers.
What we know to be ‘bedding Geraniums’ today are due to centuries of breeding from the original wild form called Pelargonium zonale. All that is left of this species in modern day plants is the rounded leaf often with a brown marking or ‘zone’ in the centre. The graceful thin petals have been bred into pompoms of gaudy coloured flowers with multiple heads per stem. At Woottens we do not grow ‘bedding Geraniums’ however we choose to propagate a few ‘select’ zonal hybrids suitable for overwintering. Pelargonium Paul Crampel is such a variety, dating back to a French nurseryman in the 1800’s from which he made his fortune and a few single zonal hybrids such as P.The Boar and P. Betty Catchpole. These are strong plants with long flower stems and pure coral single flowers
As with most plants the stellata group means ‘star like’ and refers to the shape of either the flowers or leaves or in this case both. They are deeply cut as through someone has snipped them vigorously with a pair of scissors to create the star like appearance. There are many forms of this type – Woottens currently only grow one, by request of our Pelargonium grower, Julie. The hybrid is P. Red Witch, and if Julie has her way more may be introduced into our plantlist in the next few years.
Pelargoniums, although not difficult plants, are fussy about potting compost. Multipurpose composts are not really suitable, as they lack structure and quickly collapse and become stagnant. Soil or loam based composts like John Innes are too heavy, Pelargoniums prefer compost with an open structure that does not compact over time.
After many years experimenting we have found that our Pelargoniums grow their best in a peat based compost, or peat substitute based compost. They need coarse lumpy compost that doesn’t compact. For young plants and cuttings make sure you use a fine peat based compost with the addition of grit or vermiculate for drainage. We have recently started using Dalefoot Wool Compost for seeds and cuttings when propagating. This is the best peat free substitute we have found to date. For older plants we use a peat or peat substitute compost similar to Levingtons Original, which although is classified as a multi-purpose it has additions of bark to break up the structure and improve the air content.
From the last frosts in May to the first frosts of October most Pelargoniums can live outside, in fact they benefit hugely from being in the garden during the summer months.
In the winter it is advisable to house them in the greenhouse, conservatory or in the house.
In a mild winter a cold frame may be adequate if the temperature is monitored.
The Pelargonium greenhouse should be equipped with a heater and kept frost-free at all times. While paraffin and gas burners are cheaper to run than an electric fan heater, they emit a large amount of moisture, which will increase problems with botrytis. Perhaps the best solution for the small greenhouse is to line it in winter with bubble wrap; this cuts down hugely on heat loss and makes an electric fan heater much more economical. A new technological development is the availability of remote sensors, which can be placed in the greenhouse and be monitored in the house. These require no wires and the monitors keep in touch with the sensor by radio signals. On most models if the temperature falls below a programmed level an alarm is triggered, giving you the chance to jump from your bed and clad only in night shirt and wellies…. No more waking in the morning to find your plants all frozen through, their foliage limp and black, the air already fetid with putrefaction! Thus speaks the voice of experience.
Ventilation of the greenhouse in winter. Pelargoniums hate poor ventilation as much as they do frost. Botrytis spores are always present in the atmosphere, but in a well-ventilated dry greenhouse, they will remain at modest levels. Fail to ventilate each day, and botrytis will become a major problem. We open the vent on our greenhouse for a few hours each day, whatever the temperature outside.
Ventilation of the Greenhouse in summer. We leave the vents and doors of our Pelargonium house open all summer, from the end of May to the end of September. Under glass Pelargoniums can suffer in summer with heat stress.
Conservatory – If you’re housing your plants in a conservatory remember to ventilate it in the summer as temperatures in unventilated conservatories can easily reach 50 degrees centigrade, which not only causes the Pelargoniums stress but can provide wonderful breeding conditions for whitefly and other aphids.
Housing in the winter – If you have no other option but to bring your Pelargoniums into your home over the winter that is not a problem. Try to keep them in a light, cool yet frost free room; do not sit them on a radiator to keep warm or nestled up to an open fire! They benefit from temperatures between 5-10 degrees in the winter to rest and sometimes go dormant. Kitchens and bathrooms aren’t ideal due to spasmodic moisture levels. They will require plenty of light over the winter period so garages and dark rooms aren’t suitable.
Watering & Feeding
During November Pelargoniums should be progressively dried out. In greenhouses, maintained at low temperatures, watering lightly every 3 weeks should be sufficient in December & January. The plants should be watered, perhaps, once a week in February. By the beginning of March, they will be beginning to show vigorous signs of new growth & therefore normal watering may be gradually resumed. By April, established plants can be watered every other day, a routine, which will continue until late October. It is important to remember that young plants will always need less watering, because they have less developed root systems. For this reason indiscriminate overhead watering systems and capillary matting are not suitable; plants must be watered individually. Overwatering, particularly in winter is probably the cause of more plant losses than pests and frost put together. Excessive solicitude is the root problem. The gardener, like the convivial host who forces drinks down the throats of his already inebriated guests.
Plants should always be carefully watered, ensuring the leaves receive the minimum amount of splashing possible. This is particularly important in winter, when wet leaves will greatly increase the chances of botrytis taking hold. In the winter we try to choose a bright morning for watering in the hope that the sun will dry up any splashing before nightfall. Alternatively, we water on days with a warm wind and open the doors at both ends of the tunnels to let the wind dry the leaves.
Basic rules of watering – If temperatures are warm watering can be liberal however if temperatures are cool then Pelargoniums prefer to be dry. A little similarly to us humans! Our grower Julie always advises ‘if you’re not sure if it needs water then it’s best not to water it’.
Pelargoniums, when in growth, need feeding. We mix slow release fertiliser in with all our potting compost. The alternative is to feed with liquid potassium fertiliser (I.e. Tomorite) during the growing season. Whichever method is chosen, Pelargoniums should not be fed with a high nitrogen fertiliser, which will encourage excessive foliage & weak growth. High potash feeds will give tighter plants with more flowers.
Remember that wild forms or species Pelargoniums do not require feeding as much as the blousy hybrids. The scented leaf and species forms are not highly floriferous and should be enjoyed for their foliage and form. Many have fairly insignificant small flowers.
Propagation & Potting
Pelargonium cuttings are normally taken in March/April and again in August/September. If possible cuttings should be nodal rather than internodal and should always be taken from fresh new growth. Cuttings for larger varieties may be up to six inches in length, although for short jointed varieties such as angels they may be only as much as an inch. To encourage a flush of suitable growth many growers cut back their stock plants hard, about a month or so before the cuttings are required. Before inserting the cuttings in the compost pinch off the lower leaves, leaving just two leaves at the top of each stem. With larger leaf varieties, it is advisable to trim the leaves down to about half their size; this reduces transpiration, which the rootless cuttings can ill sustain; it also improves air circulation between cuttings, thus lessening the chances of botrytis. We do not use hormonal rooting powder on our cuttings as we have found it to make no significant difference apart from providing a fungicide. We root our Pelargonium cuttings in plug trays. This provides even spacing and protects cuttings from cross infection. It also allows rooted cuttings to be potted on without root disturbance. Shade cuttings during hot weather. Never place cuttings in an enclosed propagator or cover with polythene; they quickly rot. Bottom heat does help rooting in the cooler months. Rooting normally takes places within four weeks in the spring and sometimes longer in the autumn.
With experience, growers can tell at a glance if a pot of cuttings is rooted – immediately after rooting, the cuttings put on a flush of new growth.
Potting and repotting can take place any time between February and early October. When potting or repotting, it is most important to choose an appropriate pot size. This will not only depend on the size of the plant and its rootball, but also on the vigour of the variety. Vigorous varieties such as P. tomentosum, or P. paplionaceum, when potted up as rooted cuttings, should be put straight into an11cm. pot. Less vigorous varieties such as P. Deerwood Lavender Lad or P. Angel Eyes Orange must not be overpotted and should be put first into a 7cm. pot. It is particularly important not to overpot in early spring or autumn. When plants are growing strongly, during the warm summer months, the risks are much less. When plants have been grown into large specimens and it is impractical to put them into a larger pot, their vigour can be maintained by removing them from their pot, rubbing off a portion of the old fibrous root and compost, and placing them back in the old pot with fresh compost. We repot our entire collection of Pelargoniums once a year, in August.
Pelargoniums need constant stopping, during the early stages of growth. If left unpruned, they will never achieve the strong woody growth, which is necessary for them to make shapely robust plants. Nipping back will delay flowering, but will give you large well rounded, sturdy plants, which can carry dozens of flowers, rather than one leggy stem, struggling to support a single flower. Some plants need more nipping back than others. Decorative Pelargoniums are very prone to put on excessive sappy growth if left unchecked. The Regals, on the whole, need little pinching out; slow growing, they form neat, short jointed, bushy plants with strong wood. The Scented and Uniques are a mixed bag. Most of them produce strong wood. However some like P. Deerwood Lavender Lad and P. abrotanifolium are all exceptionally lax growers and will need frequent stopping. The angels are mostly compact; P. Tip Top Duet and P. Jerey being exceptions and requiring regular pinching out.
In autumn, plants need severe pruning, to reduce the quantity of foliage, and ensure good light penetration to all parts of the plant and good air circulation between the foliage. If plants are left unpruned, there will be insufficient light for the lower foliage, and stagnant air will collect in the centre of the plant, greatly increasing problems with botrytis.
When pruning Pelargoniums, always cut them back to just above a node. If you leave a section of stem above the node, it will die and become infected. To seal the wound we now use neat liquid bleach applied on the tip of an old watercolour brush. The liquid bleach will both act as fungicide and create a very alkaline environment in which bacteria will not thrive. All cuts should be inspected at regular intervals throughout the winter for signs of infection. If the cut does become infected, it must be cut back to the next node.
One problem with Pelargoniums can be Whitefly. Whitefly, however, is not omnivorous. It spares most of the species Pelargoniums, but can be rife on citrus scented leaf varieties. However its favourite meat is Regals and Decorative Pelargoniums and it is not adverse to an Angel or Zonal. Whitefly sucks the foliage of its victims, leaving the leaves with pale mottled patches. It also deposits a sticky substance called honeydew, on which sooty moulds develop. If this was not enough Whitefly are carriers of virus from one plant to another.
To avoid chemical use on the nursery we spray our Pelargoniums regularly through the summer with a soap spray – SB Invigorator. At home you can use diluted washing up liquid. The soap blocks the aphids breathing holes and kills them. Aphids breed rapidly though so regular applications is advisable once an infestation has begun. Aphids thrive under glass so greenhouses and conservatory kept plants will suffer more. If a particular plant shows signs of whitefly put it outside away from other plants to let natural predators such as ladybirds do their work. There are biological controls available on the market for glass house whitefly – Encarsia formosa is one. See the RHS website for more details.
Like roses, Pelargoniums greatly benefit from deadheading. Fail to remove the dead flower heads, and fertile plants will normally cease flowering, and concentrate on producing seed, which is, after all, for them their botanical purpose. Remove the deadheads, and they will be thwarted from making seed, encouraging them to start flowering again. Deadheading is also vital during the winter months, as any spent flowers will immediately become infected with botrytis.
Removing Dead Leaves
It is important to remove promptly all yellow or diseased foliage. This improves air circulation, and allows more light to penetrate to the lower parts of the plant. It is much quicker not to attempt to remove the whole petiole (or leaf stem), right back to the branch. There is also a risk in trying to do so, that you may wound the stem and thereby introduce infection into the plant. If leaves are firmly nipped off with thumb and forefinger at the point where the petiole joins the leaf, the petiole will subsequently wither away, and a natural callous will form at the point of meeting between the petiole and branch. The withered petiole can then be removed with a flick of the finger.
Rust (Puccinia pelargonii-zonalis) can be identified as small circles of orange spores on the underside of foliage. It only ‘normally’ attacks Zonal Pelargoniums. Affected foliage should be picked off inside a polythene bag, as this will prevent the dispersion of the spores. All Zonals should then can be sprayed with a fungicide
Grey mould (Botrytis cinerea) is a problem of the dark days of winter. The most effective control for Grey Mould is good ventilation, a dry atmosphere and scrupulous hygiene – all dead or yellow leaves should be removed on a frequent basis. After any winter pruning, all wounds should be sealed with neat liquid bleach, applied with an old watercolour brush. All wounds should be examined on a regular basis, and if affected, the diseased limb should be cut back to just above the next healthy node.
Black leg (Pythium) This is a fungal condition, which can afflict fully grown plants, but is more often a problem with unrooted cuttings. Its main causes are cuttings not being properly firmed in and overwatering or waterlogged compost. Pots and trays of cuttings should be regularly inspected, and all cuttings, which show signs of darkening at the bottom of the stem, be immediately removed.
If you have any questions about Pelargonium problems, growing or propagation you can email our advice line using firstname.lastname@example.org
Pelargonium Events & Societies
Each year Woottens holds a Pelargonium Open Day in July where you can view all our plants in flower and talk to the specialist about growing and propagation. See our events page for details
Below is a ‘You Tube’ video of Luci showing you how to propagate Pelargoniums:
Click here to view Pelargoniums Care Notes
Pelargoniums Care Notes
COMPOST. Pelargoniums like a compost with an open structure. For potting on we recommend using peat multipurpose with the addition of about 25% coarse grit. For striking cuttings we use cocofibre.
DEADHEADING. Deadheading is essential for a continuous succession of flowers throughout the summer.
FERTILISER. Tomato fertilizer is ideal. Feed every fourteen days from March to September. Do not use a high nitrogen fertilizer.
PESTS. Pelargoniums suffer few problems apart from whitefly. This is best controlled by drenching the compost in your pots of Pelargoniums with the systemic chemical Provada (active ingredient thiacloprid) every 4 months. Caterpillars can be a problem late in the season. Use an approved contact insecticide.
PRUNING. Pelargoniums always benefit from nipping-out any weak growth. This is particularly important in the early Spring.
REPOTTING. Pelargoniums should always be repotted before they become pot-bound. Pot-bound Pelargoniums will rapidly lose their lower leaves and become gangly and unsightly.
WATERING. Pelargoniums should be watered freely during the growing season. In winter they should be kept just the moist side of dry. Pelargoniums should never be allowed to become waterlogged.
WINTER ACCOMODATION. In winter Pelargoniums need to be housed in a light frost-free environment. Good ventilation is of the utmost importance.
WINTER MAINTENANCE. Pick over plants once a week removing all dead and dying foliage.
See the Full List