The Lisbon lemon (Citrus x limon 'Lisbon') is one of the most widely-available varieties of lemon found in shops around the world. Native to Australia, they're descended from the Gallego lemon in Portugal. This is where the inspiration for their name came from.
Providing you live in a hot and dry region, you can grow Lisbon lemon trees outdoor year-round and receive an abundant harvest. These trees thrive in containers and in colder climates they can be overwintered indoors.
The lemons on these trees are bright yellow when mature, have particularly juicy, acidic flesh, and contain few seeds or none at all. Lisbon lemons are often confused with another popular lemon variety—the Eureka.
In terms of the fruit, Lisbon lemon rind has a smoother texture and a more prominent mammilla (protruding nipple). But it can still be tricky to identify the variety from the fruit alone. To make a definitive identification, you need to examine the trees the fruit comes from.
Lisbon lemon trees are thornier than Eurekas, more tolerant of the cold, and they produce more fruit. Their main crop is harvested in the winter, but, once mature, if they have the right conditions, lemons can be found on the tree throughout the year.
Unlike the Eureka, whose lemons are found on the outside, Lisbon lemons are located inside the dense, glossy, green canopy of the tree. The tree has a more upright and spreading growth habit, too.
Lisbon lemon trees can reach up to and over 15 feet when grown outdoors but are more dwarf-like when kept in containers. They also produce pretty white blooms that have a fragrance reminiscent of orange blossom.
|Botanical Name||Citrus x limon 'Lisbon'|
|Common Name||Lisbon lemon tree|
|Plant Type||Evergreen tree|
|Mature Size||Up to 15 ft. tall|
|Sun Exposure||Full sun|
|Soil pH||Tolerant of a variety, particularly acidic types|
|Hardiness Zones||9 - 11, USDA|
|Native Area||Australia with Portugese descent|
Of all the citrus fruits, lemons are the most sensitive to cold temperatures. Although Lisbon lemon trees are a little hardier than other varieties, they still need warm and sunny conditions to thrive.
These drought-tolerant trees are well suited to sheltered, sunny, desert regions, or they can be grown in containers and moved inside if frost is expected during the winter. Make sure the pot is large enough, has good draining and you select a potting mix suited to citrus trees.
Once your tree is established, don't expect it to produce a bumper crop instantly. It can take a few years before you'll start seeing lemons in the canopy.
If you don't have a garden that receives plenty of sunlight, then the Lisbon lemon tree won't be for you. This species needs a full sun position to thrive.
Lisbon lemon trees can handle a variety of soil types but have a preference for those on the acidic side, and good drainage is an absolute must.
Soggy roots are a problem for all lemon trees, and pooling water around the trunk should be prevented. If you're concerned, you could plant your tree on a mound or slope to ensure the water runs off.
Getting the balance right with watering your Lisbon lemon tree can make a big difference in terms of their vigor and fruit production levels.
While your Lisbon lemon tree is getting established, during the first few years, it'll need more watering. As it matures, it becomes more drought tolerant.
Young trees especially prefer the soil to remain moist during the summer. Slow and deep watering every fortnight is usually recommended, but in very hot or dry soils it'll need to be more often.
Excessive watering and soggy conditions, however, can lead to root rot. Be careful not to overdo it!
Temperature and Humidity
Although Lisbon lemon trees are more cold tolerant than their Eureka relatives, it's important to remember that, of all the citrus fruits, lemons are the most sensitive to cold weather. This is particularly true of young trees that aren't so well established.
If you plan to keep them outdoors, you need to have guaranteed mild winters.
Given that Lisbon lemon trees produce such an abundance of fruit, they use up a lot of energy. Unless your tree is planted in particularly fertile soil, they'll appreciate a bi-annual feed of a fertilizer specifically designed for citrus fruits.
If they don't receive enough nutrients, your crop will be diminished, the growth of the tree can be stunted, and the leaves can become discolored.
Propagating Lisbon Lemon Trees
Lemon trees are one of the easiest citrus fruits to propagate from cuttings.
These are best taken in late spring or early summer from healthy, new growth that doesn't have any fruit or flowers yet.
It can be helpful to dip the end of the cutting in rooting hormone and make sure it's potted in a well-drained medium. The medium should be kept moist throughout and covering with a bag can help to create the desired humid, warm conditions.
Lisbon lemon trees have an upright, spreading habit and regular pruning will help to keep their shape, produce a strong canopy, and encourage healthy and abundant fruit production.
Pruning is best done after harvesting, and it should involve a technique referred to as 'skirting.' By removing low hanging branches, it allows better air circulation and reduces the chance problems with fungal diseases and pests developing.
Mulching isn't recommended with lemon trees as they don't like soggy conditions. If you're expecting frosts, it's better to keep them in a container that can be moved inside for overwintering.
Select a warm and sunny spot if you want your tree to continue producing fruit.