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Lubera stops plant deliveries to the UK
Due to Brexit, we are not able to deliver to the UK. We are working on a solution on how we can continue to bring a wide range of Lubera plants to the UK and directly to our customers' homes in the future. However, such a solution will not be available before 2022 or 2023.

Citrus podcast


Hello, I'm Emma and this is the first in a series of podcasts for Lubera, a Swiss company that is bringing lots of wonderful fruit varieties to the UK. Lubera breed and sell reliable varieties of plants that have been bred specifically for gardeners. And they sell established, larger plants that mean you get to enjoy your fruit a lot sooner. 

The people at Lubera really know fruit, and they have lots of growing advice, and recipes and fascinating stories about the history and uses of plants, and we're going to be sharing some of those stories with you over the coming months.


For the first show, I caught up with Lubera boss Markus Kobelt at the Garden Press Event in London in the middle of February. The Lubera team were unveiling their 2017 catalogue, including an amazing new range of citrus plants - so I asked Markus about those.

Emma: So, in the UK we don't grow that much citrus, because the plants come from warmer climates and they're quite hard to look after over the winter, but I think you've brought some new hardier varieties?

Markus: Not special hardier varieties. We brought a very broad assortment of citrus. So we want to have the whole citrus story in our shop, and perhaps we want to sort of finish the way [journey] citrus has done in the last couple of thousand years, because it started in India and China at the foothills of the Himalaya, and then it went in the direction of today's Iran. So the Medians had citrus, then it came to Palestine, and then the Arabs and the Jews brought citrus all over the Mediterranean. So it was the Arabs who brought many citrus varieties, especially bitter oranges, to Sicily, to southern Italy, and then they started going north. 

And in the Renaissance, all the kings and dukes had orangeries. First in northern Italy, in Tuscany, so the Medici family (for example), and then all the others did the same. And in the end they started, beginning in northern Italy, to have container cultures, container plants, because it was not possible there to cultivate oranges, lemons and citrons without pots. You have to bring them inside to shelter them over winter, and so these were the first container gardeners. The first urban gardeners, perhaps.

And in the end, when we start again to have more citrus in our gardens, on our balconies, on our patios, it's to end this way [journey] that the citrus started some thousand years ago. And from the point citrus started in India and in China, it has - most of it, not all varieties - but many varieties have a fantastic adaptability to temperatures about zero degrees. So they won't survive, most of them won't survive temperatures much below zero degrees, but in the moment you have them at five to ten degrees they stop almost 100% their life. They are sleeping...

Emma: dormant?

Markus: Dormant. They have green leaves, they have a reduced activity, and so it's a possibility that we can overwinter them. We just push the button and they stop for some months, and so they can survive. And those are also the biggest mistakes people are doing when cultivating citrus in their gardens. 

Emma: So... we have a tradition in the UK of rich people with big houses having orangeries. It's not something within the reach of the.. sort of... average urban gardener. But these days we're sold them as house plants, essentially. I struggle with them indoors.

Markus: Yeah, that's right. It's one of the biggest mistakes to cultivate most citrus varieties - beside Calamondin, which is a hybrid between mandarin and kumquat, this is possible to grow inside, also to overwinter inside. But it's the biggest mistake to cultivate citrus inside, because in the winter we have a systematic problem. We have enough heat inside, but we have not enough light. Especially in the UK, if I dare to say it!

And so it's much better to push the button and stop the plant over winter, to have it cooler, and then they don't need too much light. If they have only heat, and no light, they become crazy. 


Emma: So, in an ideal situation, if somebody is growing a citrus plant and it's been maybe outdoors over the summer and it's in a pot, where should they keep it over winter? 

Markus: I think a garage with two windows is possible. If you have no windows, or something, you can also have artificial light in it. But what I have seen also, with friends, a garage with two windows on east or west or south side, it works rather good. Some varieties, in some years, will lose some leaves. Not all, but some of them. And don't panic! The worst thing when they are losing the leaves is when you are going to give them more heat. Then they become crazy, totally crazy. So you have to overwinter them cool between five degrees and ten degrees, and then in spring you even can take off the rest of the leaves. You cut them back 30%, give them fertiliser, and then they start fantastically. Of course, in this year, you will not have the biggest crop, but you have a nice plant, so it's possible. 

And I think that the biggest problem in citrus cultivation at home is when you bring them, really, inside. So we are starting to produce some hardier varieties ourselves. The most common is Poncirus trifoliata [also known as Citrus trifoliata], which is losing the leaves over winter, so it has an absolute, 100% winter hardiness. It's a bitter orange, too, so you can use it for marmalade. It's not eatable fresh. And with this type, Poncirus trifoliata, which in principle is also a citrus variety, there are big discussions inbetween scientists if there are different genes or not, but with trifoliata you can... It's very interesting, in citrus that you can breed almost all types of them with each other. And that's the reason, also, in the shops you find so many new varieties and types of citrus and so in the past and also in the future with this trifoliata were made many, many crosses to have varieties which are hardy to minus ten, twelve degrees, and from these types we will grow more varieties in the future. And these types we will try to grow ourselves.

Emma: Do you have any idea how long that breeding process might take?

Markus: No, there are varieties. And they are only in specialty nurseries, so we have to grow a little bit more to have enough stuff, which is always a problem. And we start growing ourselves some of this stuff, so in two to three years we will have our own plants of this more hardier stuff. But don't panic about the more southern varieties! I think it's also an important thing that you have a southern feeling in your garden, with, really normal citrus varieties, and it's really possible. People have... are too much afraid about growing citrus. When the kings and dukes were able to do it, you will also be able to do it nowadays. It is three or four hundred years later. 

Emma: So then, which of these southern varieties are you adding to your catalogue this year? What will people be able to buy this year? 

Markus: Yeah, this year we have a very... I think one of the biggest assortments in German-speaking, perhaps also in the UK. We have 60 varieties, all types from kumquat, winter-hardy varieties, to mandarins, tangerines, clementines. We have real, the old citrons, we have lemons, we have limes... so really a vast assortment. Not the biggest numbers by variety, because we start with citrus, so if you want to try this or that variety it's rather important to book early and to order early because they will [sell] out and we will only have them again next spring. So we are starting to ship them about middle of April. 

Emma: OK, so if somebody wanted to make their own marmalade, what would you recommend that they buy? 

Markus: There are interesting bitter oranges in our assortment, which is not really a big problem to grow. They were also the first citrus trees coming to Europe via the Arabs in the 9th and 10th century, and I think they are not really a problem. I think also very interesting the very old type of citrons - not lemons - which have a very thick white albedo [pith] and almost no fruit flesh. Because culinary, but also for the perfume they are very interesting. Culinary, they are interesting because you can use them to produce zitronat [candied citron/lemon peel] with them.

Emma: Do you mean the zest? You just take the skin off?

Markus: Yes, you take the skin off and then you cook it with sugar. I think somewhere we have also a recipe, how to do it. And then you can use for cakes, or whatever. You find it in many Italian sweets. Zitronat and also Orangeat [candied orange peel]. They have also a cultural use, some of them. Like the Buddha's hand is used by Indian people, as a gift for the new year. And the Etrog citron is used by the Jews for their festivities. And that's also a reason they came all around the Mediterranean, through the Jews, going from Palestine all over the world. 

Emma: So I think people would be very excited about growing their own lemons, so either for a nice slice of lemon in your gin and tonic at the end of the day, or even to squeeze on their pancakes, later on this month. So do you have a favourite lemon variety? 


Markus: Within the lemon I think one of the easiest and nicest growing is Meyer lemon, which was found by a plant hunter, Mr Meyer, who was working for the USDA, beginning of this century [actually the 20th century] in China. He died, tragically, also in one of his trips, I think the trip after he found the Citrus meyeri. He died, in the middle of China. And he was in charge for the United States Agriculture Department to find new varieties in China and on one of his trips he found this Meyer citron. Which is, I think, which is not really 100% lemon but which is a cross between a lemon and a mandarin.

Emma: It's a little bit sweeter, isn't it?

Markus: Yeah, it's a little bit sweeter. And it has a very round, very round growth. And that's often the case. It's not so very clear which citrus fruit is belonging to which group, because they are crossing all over, artificially done by human breeders, but also in nature. We have also a variety which all the citrus, citrons or lemons, like you say in your language. In our German language it is all the same, a citron is a citron and a lemon, but here all the lemons are... which is important... and it's also a reason why people were so excited in the Middle Ages or before the Middle Ages in the Renaissance, about lemons... because they are at the same time blooming and having fruit. And they have blooms all over the year. And one variety which is especially good to have blooms all over the year, and fruits all over the year, is the Four Seasons citron, which I can also advise to have in your garden.


Emma: The flowers, they are very scented, aren't they? Citrus flowers, they are lovely. 

Markus: What is also very interesting, when they are closed they are violet, and then opening they are becoming white. 

Emma: Very pretty! 

Markus: Yeah, it's very pretty.

Emma: So if somebody bought a lemon tree this year, how soon could they expect fruit?

Markus: Depends a little bit on the plants. I think about 60% of the plants will have flowers or young fruits in spring, this spring, when they are buying. We cannot give 100% guarantee, but what is also clear - first we are selling which have fruit on them, and then the other ones, so when you are ordering early, the early bird...

Emma: ...gets the fruit! 

Markus: Yeah, not the worm! 

Emma: So if somebody buys a new plant this year, how do they look after it, in terms of water, and fertiliser? 

Markus: In terms of water, I think, it's good to have a regime which is not... how do you say... which is flexible. Because, think about, think about a citrus tree like about you. When it's very hot, you are... you need more water not less. So I think watering citrus plants, the most important thing is not the amount of water you are giving, because in the south, remember being in the south and being in the rain, when it's raining it's raining like crazy. And it's a good thing to water them like crazy when you are watering them. But the most important thing is that the water is going out, down there. So when repot, for example, citrus it is very important to have down holes [drainage] in the pot, a level with some stones or whatever, that really the water is going out. 

Emma: So plenty of water, but very good drainage.  

Markus: Yes, that's the most important thing. 

Emma: And it sometimes seems to me that fertilising citrus is complicated.

Markus: Not really. They need a little bit more of iron than other plants, and a slightly acid soil, but most pot soils you are buying have the right pH. I would use, personally I would use a citrus fertiliser. We have, ourselves, a new citrus fertiliser - Instant Citrus. So our fertilisers are named Fruitilisers! And so this one you give every time you are giving water, with the water you are giving this fertiliser. This is one of the easiest... if you have a bigger pot, you can work also with a long term six- or nine-month fertiliser. So this gives you the basic food for the plant and additionally then you can have about half the normal doses of the fertiliser you are giving with the water.

Emma: OK, and in the winter when the plant has gone dormant, you don't... very little water, no food? 

Markus: Yeah, no food, you stop giving food in October, and you are also going down with the water. And in the winter you have it dry. In the winter only giving water really when the first ten, fifteen centimetres are 100% dried out. Because you want to stop the plant, you want to have the plant sleeping a little bit, and if you awake it you have a problem. 

Emma: How often will they need repotting?

Markus: So buying a young plant or a fresh plant from the nursery, normally it is grown out. So if you are buying early it's even possible to repot it in the first year. Otherwise in the second year, normally, because the pots are not too big. So if you are changing pots, normally choose a pot with about three to five... which has a diameter which is about three to five centimetres bigger than the pot before. You take out... and repotting, the best thing is just before the normal vegetation period is starting, so in March, beginning of April. So you can do it in the shed, or in the garage or whatever, just before you bring the plants out. And then you take also out there a little bit of the old pot soil off, and then you fill the new space with new pot soil. If you have a very big plant, it's also possible to repot in the same pot, and then you have to take off five centimetres, so really with a knife, take off the old roots and also the old pot soil, and then you can fill again. So the plant is rejuvenated. Especially if you repot in the same pot size, you have also to prune down a little bit the plant, by 10-30% to have more growth. In the end, this is also one of the miracles, or one of the findings the Renaissance gardeners had. Because they had very big plants, and they couldn't grow any more, because they had no place in the their glasshouses or orangeries. So they could have them at the same size for sometimes 300, 400 years, so repotting in the same pot, taking off some of the roots and soil and cutting them back. 

Emma: So I have a lemon tree that I grew from a pip, several years ago. It must have at least seven now, and I've nearly killed it at least twice with the cold, but it's still alive. But it has never fruited, do you think it will ever fruit?

Markus: Yeah, it will fruit, if you have enough time. So all plants grown by seeds have a juvenile phase, so they are not adult. So then they come into puberty, and they have fruits. And so that's the difference between fruits you grow from seeds, and fruits that are vegetatively propagated by grafting. The grafted trees will have fruits much earlier, because you use wood which is already adult, and so the plant is suddenly - after one or two years - in an adult stage and able to produce fruits. Whereas, the other plant from seed has to have some time, sometimes, seven, eight, nine years, to be in a state to have fruits. Normally also these young trees have even more thorns...

Emma: It's very thorny!

Markus: ...than the really cultivated and grafted trees. 

Emma: But there's hope for it yet, then? But if I want lemons this year I should buy one of yours!

Markus: Yeah!

Emma: OK, well thank you very much for talking to us today, Markus.

Markus: Thank you Emma.

Emma: This is just the first of many shows. We're going to tell lots of stories, because you have some wonderful stories to tell about your Lubera fruitful gardening, you're developing fruit and ornamental plants specifically for gardeners and to grow well in gardens, so I think that's a very interesting story that people are going to want to hear! 

Emma-Cooper     Emma Cooper





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