Citrus × limon (Lemon)

Parentage and cultivated origin of Citrus × limon (Lemon)

Citrus × limon is a cultivated hybrid with ancestry from Citrus maxima, Citrus medica and Citrus reticulata.

The lemon developed through a long history of cultivation in Asia and travelled west through Persia and the Arab world before becoming deeply established around the Mediterranean.

Growing Citrus × limon (Lemon)

• Light and flowering: Give Lemon direct sun indoors and gradually introduce it to an outdoor position in warm weather. Bright light supports compact shoots, reliable flowering and full fruit development.
• Temperature and slower growth: Use 18–28 °C as the normal growing range and protect it from extended periods below 5 °C. When indoor light is lower, choose the brightest frost-free position available. Cooler conditions can slow growth, so reduce water and fertiliser to match.
• Humidity: Maintain moderate indoor humidity around 50–60%, keeping the crown away from icy glass and hot radiator air.
• Watering: Let the surface dry and wait until the deeper mix is only lightly moist before watering again. Water thoroughly before a fruiting root ball becomes dry throughout, then let excess water drain.
• Mix and repotting: Use a firm but porous citrus mix and keep the plant at its original depth with any graft point above the surface. Repot when roots are densely packed or the mix has become compact and slow-draining.
• Feeding: Use a citrus fertiliser while the plant is growing, flowering or developing fruit.
• Pruning and crop support: Prune lightly after harvest or once new growth has firmed up, retain leafy side shoots and support branches carrying several heavy lemons.

Lemon leaf, root and pest problems

• New leaves curl around silvery winding trails: Citrus leafminer has fed inside tender tissue. Older firm leaves remain marked and can continue supporting the plant; keep leaves that remain mostly green and inspect the next round of new leaves before deciding whether any shoot needs pruning.
• Older leaves turn evenly yellow: A lack of nutrients can cause this, but damaged roots and poor drainage can produce a similar pattern. Check the roots and drainage first and compare the leaf pattern with the yellow-leaf guide before increasing fertiliser.
• Sticky residue, shell-like bumps or black surface growth appears: Scale insects produce honeydew that supports sooty mould. Isolate Lemon, remove visible insects and clean the residue. When scale requires treatment, choose a product labelled for scale and the plant and follow the label for every repeat application. The scale guide shows what to look for.
• Yellow leaves accompany a wet, sour-smelling pot: Inspect the roots before adding more water. Using clean, disinfected tools, cut away soft or rotten tissue back to firm, healthy tissue and discard the removed material. Replace dense waterlogged potting mix and keep the trunk base above the mix so the bark can dry between waterings.

If the cause is still unclear, send us clear photos of the whole plant, the affected area and the potting mix so we can help you narrow it down.

Keep Citrus × limon (Lemon) away from pets

• The fruit flesh is edible, while leaves, peel and other plant material can irritate cats and dogs.
• These parts contain essential oils and psoralens that may cause vomiting, stomach pain, unusual tiredness or skin irritation.
• Contact a veterinarian if a pet chews the plant or develops symptoms. Seek medical advice if a person becomes unwell after exposure.

About the name Citrus × limon

Citrus is the classical Latin name used for citron and related citrus plants. The epithet limon preserves an old word for lemon that entered European languages through Arabic and Persian.

Carl Linnaeus established the genus Citrus in 1753 in Species Plantarum, page 782.

Carl Linnaeus first described it as Citrus medica var. limon in 1753 in Species Plantarum, page 782. Pehr Osbeck later placed it in Citrus as Citrus × limon in 1765 in Reise Ostindien, page 250.