Garden Care Guide

Siberian Elm Care

Ulmus pumila

A very fast-growing tree that is extremely tolerant of harsh conditions such as heat, cold, drought and poor soil. CAUTION: Because of its weak, brittle branch structure and its uncontrolled spread by dropping abundant seed, it is considered an invasive and problematic tree in many regions.

Hardy · -40 °C / -40 °F

Monthly care calendar

Timings are for a temperate Northern Hemisphere climate. In warmer areas tasks start earlier, in colder areas later; in the Southern Hemisphere shift them by six months.

January
  • Watering: Not required; the plant is dormant and winter rains are sufficient.
  • Pruning: This is the best time to strengthen weak branch structure and remove branches at risk of breaking.
February
  • Pruning: While dormant, remove dry, broken, crossing and inward-growing branches so that air and light reach the inside of the crown.
  • General care: The plant wakes up very early.
March
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Even before the leaves are fully grown, it produces plenty of seeds (samaras) and scatters them around.
  • Pests & diseases: During humid and cool periods, monitor the leaves and trunk for signs of mold, spots and rot.
April
  • Watering: If there is no rainfall, water every 15 days.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Remove unwanted seedlings that have sprouted from seeds scattered around.
  • Pests & diseases: Look for aphids (green or black clusters of small insects) on fresh shoot tips. If there are only a few, you can knock them off with a strong jet of water.
May
  • Watering: If there is no rainfall, water once a week.
  • Fertilizing: Absolutely do not fertilize; it weakens the branches even more.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Spread a 5-7 cm layer of mulch over the root zone; it retains soil moisture and suppresses weeds. Do not pile mulch against the trunk.
  • Pests & diseases: Look for aphids (green or black clusters of small insects) on fresh shoot tips. If there are only a few, you can knock them off with a strong jet of water.
June
  • Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. The root zone should be wetted to a depth of 30-40 cm.
  • Pruning: Remove branches broken by the storm.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Continue removing unwanted seedlings under the tree.
  • Pests & diseases: Look for aphids (green or black clusters of small insects) on fresh shoot tips. If there are only a few, you can knock them off with a strong jet of water.
July
  • Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. The root zone should be wetted to a depth of 30-40 cm.
  • General care: Tolerates extreme heat without problems.
August
  • Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. The root zone should be wetted to a depth of 30-40 cm.
  • General care: It gradually prepares for winter.
September
  • Watering: If there is no rainfall, water once a week.
  • Fertilizing: Absolutely do not fertilize.
  • Pruning: Unless there is an emergency (such as a broken branch), wait until winter.
  • General care: The most important cultural task for this tree is to pull up unwanted seedlings that appear around it throughout the year and keep its spread under control.
  • Pests & diseases: It may have been damaged by leaf beetles during the summer, but this usually does not kill the tree.
October
  • Watering: If there is no rainfall, water every 15 days.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: The leaves turn yellow and begin to fall. You can clear the fallen leaves.
  • Pests & diseases: During humid and cool periods, monitor the leaves and trunk for signs of mold, spots and rot.
November
  • Pruning: After the leaves have completely fallen, pruning can be planned.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Collect fallen leaves; many disease agents and pests overwinter under leaves.
  • Pests & diseases: During humid and cool periods, monitor the leaves and trunk for signs of mold, spots and rot.
December
  • Pruning: This is the most suitable period for pruning.
  • General care: The tree is fully dormant.

The care advice on this page is general and for information only; it is not professional advice. Plant age, soil and your garden’s microclimate can change the outcome. Plant protection products are mentioned only as general information; they are regulated, and the choice, dose and timing must be decided by a qualified professional under local rules. Consult a landscape architect or agronomist before applying.

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