Watering Japanese Maples

Japanese maples, Acer palmatum, are beloved plants in the home landscape. These shallow-rooted trees are well adapted to drier conditions but grow best when the soil is evenly moist. In fact, it is much easier to overwater a Japanese maple than it is to underwater it, so care must be taken to ensure that your Japanese maples will thrive for decades. Read on to learn how and when to water your Japanese maples.


How To Tell If Japanese Maples Need Water

A general lack of precipitation means that your Japanese maples will need water. To be sure, check to see if the soil is dry or cracked. If the soil feels dry, it is a good time to water. A Japanese maple that needs to be watered will often have leaves that are wilting or dry; overwatered Japanese maples usually have yellowed and blackened leaves. Take caution to not overwater because this can cause the tree to rot.

How Often To Water Japanese Maples

Newly planted Japanese maples need to be watered immediately after planting. This helps to settle the soil and reduces the effects of transplant shock while encouraging healthy root establishment. In general, newly planted Japanese maples should be watered more frequently than mature, established trees. Water your recently transplanted Japanese maples every 1-3 days after planting, gradually decreasing the frequency to just once per week for the first growing season. Monitor soil moisture levels during the second and third years of growth, and water your Japanese maples as needed. 


For established Japanese maples, the soil should be kept uniformly moist. Often, normal levels of precipitation are enough to keep Japanese maples sufficiently watered. Well-established Japanese maples are fairly drought tolerant but will show signs of stress if dry conditions persist. Water mature Japanese maples during periods of drought and extreme heat or after applying fertilizer. 

Japanese maples growing in containers will need to be watered more often than Japanese maples growing in the ground. Potting soil tends to dry out faster than ground soils, and the restricted growth area of containers lessens the overall water-holding capacity. If the potting soil is dry, it is time to water your Japanese maple. Water the plant until water starts pouring from the drainage holes, and empty the collection tray of any standing water. Potted Japanese maples need to be watered at least 3-4 times per week, depending on temperature and precipitation level. 

Best Time To Water Japanese Maples

The best time of the day to water Japanese maples is during the morning, which allows plenty of time for the roots to soak up the water. If watering during the evening, try not to get the leaves wet, as the slower evaporation time at evening and night can facilitate the spread of diseases. Japanese maples can be watered throughout the entire growing season, starting in early spring when they begin to leaf out. Water your Japanese maples deeply in late fall before the ground freezes. Japanese maples do not need to be watered during the winter unless you are applying fertilizer in late winter. 

How to Water Japanese Maples

Step 1 - Find the drip line.

The drip line is located on the ground, directly below the circumference of the tree’s canopy. This is where the majority of the feeder roots are located, so water should be applied around this area for established trees. For newly planted Japanese maples, applying water to the area of the root ball is sufficient. 

Step 2 - Water the Japanese maple.

Using a hose, deeply water the tree by applying water to various points around the drip line until the soil is evenly moist. If desired, install an automatic irrigation system, such as drip irrigation, around the drip line or root ball to save time on watering. This may be especially helpful for newly planted trees that need more frequent watering. Set the timer to only water during the morning or whenever there is insufficient precipitation. 

Step 3 - Apply mulch.

Mulching is an excellent way to conserve soil moisture for Japanese maples. Apply 2-3 inches of wood-based mulch, spreading it smoothly above the plant’s root system. To prevent rot, apply the mulch several inches away from the Japanese maple’s trunk.

Japanese Maple Watering Tips

  • Water Japanese maples in the morning 
  • Newly planted trees need to be watered more often than established trees
  • Apply water to the tree’s drip line
  • Water established trees during drought periods
  • Applying mulch helps to conserve soil moisture


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 Lauren Youngcourt - Published 04-28-2023