Geranium 'Balcon Mix' from Thompson & Morgan
Healthy geraniums produce excellent, long-lasting flower displays
Image: Geranium ‘Balcon Mix’ from Thompson & Morgan

If you’re looking for answers to your geranium and pelargonium troubleshooting questions, you’ve come to the right place. Here are some timely tips on everything from encouraging more flowers to making your plants more compact. Geraniums are easy to grow, and some of the most common problems are easily solved with a bit of additional care. Here’s how to rejuvenate your geraniums. 

What should I do if my geraniums aren’t looking very well?

Geranium 'Rosebud Collection'
Healthy geraniums should have bright green leaves with vigorous growth
Image: Geranium ‘Rosebud Collection’ from Thompson & Morgan

Are just a few leaves turning yellow or is the whole plant looking a bit sick? If it’s just a few leaves and the rest of the plant is looking robust, then it could be due to a sudden change in temperature. When plants are moved outdoors from a sheltered area, they can have a bit of a ‘shock’ at the change and lose a few leaves.

If the whole plant is looking poorly, take it out of the pot and have a good look at the roots:

  • If the roots are nonexistent then I’m afraid it suggests that something has got into the soil and eaten them. This is most probably vine weevil. Have a look for the grubs – although they’re not always obvious to the eye. There are treatments available, so don’t panic. If the plant has any healthy parts remaining, take a cutting to root.
  • If the roots are abundant but brown, the root system has died. The most common cause of this is overwatering or a problem with the compost. As before, there is little that can be done apart from taking a cutting from any remaining healthy growth.
  • If the roots are lovely and white and there are plenty of them, then your plant has a chance! Looking sick is an indication that it’s not happy about its current conditions. Remember that these plants originate from South Africa so try refreshing the compost, moving the plant somewhere very warm and light and making sure the compost is moist. Finally, give it a feed and usually the plant bounces back to life.

Even when you do manage to get a plant to recover, review your general growing conditions and watering habits to reduce the likelihood of further problems. However, there is no such thing as 100% success rate – we gardeners can only do our best!

What sort of compost should I use to pot up geraniums?

Watering geraniums in a pot
Choose the right compost to keep geraniums healthy
Image: Encierro/Shutterstock

The choice of compost is very important, always go for a general purpose type – but if you have a favourite that works for you, stick with it. Avoid bark based and coir compost for geraniums as they hold too much moisture. And if you do want to try something new, test it on a few plants first!

To determine if a compost is light enough for geraniums, squash a damp ball of it in a tight fist. When you open your hand it should fall away freely and not stay in a tight hard ball. Most modern composts don’t need any additional drainage material added as they’re designed for general use.

Change the compost for container grown plants every year. Geraniums will grow for years if you keep them away from frost, but over time the compost becomes compacted and crushed down from constant watering. The root system of the plant needs oxygen which is less available in tight, hard compost. Freshening it up will not only provide a boost of nutrition, but will also be nice and light so that the plants can spread their roots happily.

The choice of compost is very important, always go for a general purpose type – but if you have a favourite that works for you, stick with it. Avoid bark based and coir compost for geraniums as they hold too much moisture. And if you do want to try something new, test it on a few plants first!

To determine if a compost is light enough for geraniums, squash a damp ball of it in a tight fist. When you open your hand it should fall away freely and not stay in a tight hard ball. Most modern composts don’t need any additional drainage material added as they’re designed for general use.

Change the compost for container grown plants every year. Geraniums will grow for years if you keep them away from frost, but over time the compost becomes compacted and crushed down from constant watering. The root system of the plant needs oxygen which is less available in tight, hard compost. Freshening it up will not only provide a boost of nutrition, but will also be nice and light so that the plants can spread their roots happily.

How can I stop my geraniums looking too leggy?

Geranium 'White Rose' from Thompson & Morgan
Geranium ‘White Rose’ is bred to have long trailing stems suited to hanging basket displays
Image: Geranium ‘White Rose’ from Thompson & Morgan

Most modern geraniums are bred to have stems with short joints between the nodes. This results in short, bushy plants which don’t need much attention. Exhibitors growing plants for showing will spend a lot of time pinching out the growing tips of their plants to encourage the production of compact bushy growth. 

Older varieties and more mature geraniums grow vigorously upward, and can look too stick-like with little top growth. If you aren’t fussed about a show of flowers from your leggy plant this summer, give it a good chop in late spring. If you want flowers over the summer then wait until the main flower display is over. 

Use a sharp knife to cut the plant back, and always cut just above a leaf joint in a straight line. The plant will heal over at this point. By cutting the plant back you’re forcing it to send out more growing shoots and it will do this from lower down, making a bushier plant. If you’re nervous about causing harm, start with one plant. You can take geraniums right back to 5 inch sticks and the plant will still produce a load of new healthy growth.

How do I get my geraniums to flower more?

Geranium ‘Tall Dark & Handsome Hot Pink’ from Thompson & Morgan
Geranium ‘Tall Dark & Handsome Hot Pink’ produces dark foliage and bright pink flowers
Image: Geranium ‘Tall Dark & Handsome Hot Pink’ from Thompson & Morgan

The ideal flowering environment for geraniums is a warm, light place with good compost that’s kept moist, but not waterlogged. Pots must have drainage holes in them so that they’re not sitting in puddles of water. Geraniums need oxygen around their roots which is why overwatering needs to be avoided.

Giving your plants a regular feed of special geranium fertiliser will significantly increase the number of flowers you get. Feed them every week – the fertiliser contains high levels of potash which encourages flower production. It doesn’t take long and the results are well worth the little effort involved. Having gone to all the trouble of planting out a display, it makes sense to get the best show possible from it. The same goes for all your flowering plants. Use a special container fertiliser for all your potted fuchsias and patio plants, and try a once a year fertiliser for shrubs in the border.

Where should I plant geraniums for the best results?

Geranium 'Summer Lovers Collection' from Thompson & Morgan
Plant your geraniums in a sunny border for the best growth and flowering results
Image: Geranium Summer Lovers Collection from Thompson & Morgan

Geraniums love warm, sunny positions but will still do very well in areas of part shade. Spread your geraniums around through beds and borders, avoiding deep shade and waterlogged areas. Perfect for containers, geraniums are an easy way to brighten up your whole garden, including hanging baskets and window boxes. Unlike other plants, they don’t flag in the heat, so they’re especially good for drought-prone areas. For the best results, ensure they’re kept moist and receive some sun each day.

I hope we’ve answered your geranium plant questions and concerns. For more information about growing and caring for pelargoniums, head to our geraniums hub page for more help, tips & tricks! Share your geranium photographs via our social channels using the hashtag #YourTMGarden.

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