Tulip fire is a fungal disease that affects tulips, and anecdotal evidence suggests that the spring of 2023 was a bad year. As a result, some high profile gardens are not planting tulips.
Sissinghurst Castle Garden in Kent will not have any tulip displays in 2024, following an outbreak of tulip fire around the garden this spring. Head gardener Troy Scott Smith and his team have dug up all infected tulip bulbs in the garden, including some species tulip varieties, and are not planting any this autumn (or for several years).
At nearby Perch Hill, bulb supplier and gardener Sarah Raven has also dug up thousands of infected bulbs, and will only be planting tulips in sterlised pots this year.
Do we need to worry about tulip fire?
"The ideal conditions for the fungus are damp conditions in combination with high temperatures," explains Dutch bulb expert Carien van Boxtel. "This wet spring with high temperatures proved to be ideal for tulip fire."
Sarah Raven is keen to point out that tulip fire is not a problem every year, and says that not every tulip in her garden was affected this spring. “I remember that around 15 years ago, both Monty Don and I had really bad years of tulip fire as we had a pretty wet March and April. We both did the same – we both didn’t plant more tulips in our borders. The tulips came up the following year and there was no tulip fire at all. And we haven’t had it at Perch Hill since, until this last spring. And really quite a lot of tulips, even in our borders, didn’t get it. I’m really hoping this year was a blip, not a trend.” She adds: "This last wet spring was unprecedented so far, but we don’t know if that’s an aberration or a trend.”
Bayntun Flowers' Polly Nicholson, organic flower grower, florist, holder of the National Collection of historic tulips, told us: “This has been a tricky year for tulips, due to the incessant rain and warm temperatures throughout the month of March, at a critical time of growth. Many growers feared that their crops and stocks had been struck by the dreaded tulip virus, but much of the damage was simply weather related and not Botrytis tulipae. When I harvested the bulbs in July I inspected them very carefully for signs of damage (usually presenting as black spots under the bulb tulips) and they were nearly all lovely and clean. Any suspicious looking ones were thrown on the bonfire, rather than the compost heap.”
"Commercial growers have a wide range of fungicides to control tulip fire, including some acceptable for organic regimes," explains Guy Barter, chief horticulturalist at the RHS. "The incidence of the disease depends largely on the success or not of tulip producers in Holland in keeping stocks free to avoid inadvertent sale of infected tulips, which presumably depends on weather in the Netherlands.” He adds: “There is no reason to forswear tulips this autumn except in areas where the disease has occurred in the previous year or two. But gardeners of a nervous disposition may wish to grow them in containers.”
How to prevent tulip fire
Give them the right conditions
Plantswoman and bulb expert Jacqueline de Kloet points out that tulips are demanding bulbs. "They need perfect circumstances to be able to perform well. They should be planted in November when the soil has cooled down a bit, they should be planted deep ( at least at 15 cm depth) in a well-drained, not too poor soil in a sunny spot. They need lots of sunlight and warmth. And they are greedy, so I use organic fertiliser when they start to grow, in February-March."
Plant bulbs further apart
“To prevent tulip fire I recommend planting the tulips a little further apart than normal, to allow air circulation and to prevent diseased parts of one tulip from touching another," advises Polly Nicholson. Bayntun Flowers is certified with the Soil Association and so relies on organic methods and careful husbandry to prevent and limit infection. "Carefully remove any tulips that are spotted and mouldy, making sure to disinfect tools afterwards, and don’t let spent petals build up on the soil."
More on how to prevent tulip fire
Rotate your tulips
"A high fungal risk arises if you plant tulips in the same soil for several years," explains Carien van Boxtel. "Tulip residues left behind in and on top of the soil are affected by Botrytis during the dying process. This fungus will remain in the soil via sclerotia (small black seed-like structures produced on the dead tissue) and can contaminate the soil but also the outer bulb scales. If the weather is reasonably dry in spring during the growing period, the fungus has little chance of spreading and infecting surrounding leaves and flowers. But during a wet spring chances are that your tulips will be affected."
Many gardens rotate the areas where they grow tulips, so that disease does not build up in the soil. Polly Nicholson operates a four-year rotation in her cut flower field. "A bed which has been planted with tulips for cutting remains tulip-free for three years, to allow any pathogens lurking in the soil to dissipate.”
“As we rotate our big display areas of tulips, we have managed to avoid any major incidents of tulip fire so far," says Arundel Castle's head gardener, Martin Duncan. “However at the first sign of any tulip fire we remove the whole bulb.”
Matt Pottage, curator at RHS Garden Wisley, does something similar: “We do worry about tulip fire in ‘bedding tulip’ situations where we occasionally bed in ‘one hit wonders’ – we then rest the ground for a couple of years afterwards. We find on the Wisley sandy soils the disease is readily active and repeat planting always becomes affected by it, especially if the ground has been wet over winter.”
Dig up your tulips, dry them over summer and replant the following autumn
"Always dig your hybrid tulips bulbs up and store them dry in summer," advises Carien van Boxtel. "There is no guarantee that they will perform as well as the first year, however. "Deadhead your tulips before digging them up and dispose of the petals." Do not leave petals on the soil.
Grow tulips in grass
“We’ve had really good success with growing the species varieties in grass," says Sarah Raven. "In grass, you don’t get the fungal spores spotting upwards as you do from soil. We had no tulip fire at all on various species varieties such as ‘Little Beauty’ or on the Tulipa clusiana types.”
At Wisley, 100,000 bulbs were planted for its tulip festival this spring. "We have removed all areas of bedding display, but for our huge tulip festival we simply planted them through the lawns, then mowed them off and composted them afterwards," explains curator Matthew Pottage. "It involved very little soil disturbance and no extra input of fertiliser or water. The response from the visitors (feedback and visitor numbers) was phenomenal – people love to see ‘massed’ tulips and a sea of colour no matter what the good taste brigade stipulate."
Grow tulips in pots
Growing tulips in sterilised pots, in fresh compost, means you can still enjoy visual impact around the garden, even if tulip fire has been an issue. Arundel Castle, which is known for its fabulous tulip displays, usually around 400 pots of them, in fresh organic potting compost with good drainage.
Sarah Raven is still planting tulips in sterilised pots this autumn, and is going to experiment with a homemade prophylactic organic fungicide - a mix of bicarbonate of soda, liquid soap and sunflower oil in water. The fungus has already proved very effective on ranunculus in the greenhouse, which are very prone to mildew. "In some areas of the garden we’re going to treat the tulips from the moment they shoot, in March, right the way to when they finish, and in other areas we’re not going to treat," she explains. "However if we happen to have a dry spring, we won’t know if the bicarb has worked.”
Were you affected by tulip fire this year? Here are some other beautiful spring bulbs to grow.