WateringTimesWatering plan, $19
Agastache rugosa, WUCOLS IV

How often to water Korean mint in California

In July in the Central Valley, established Korean mint in loam needs a deep watering about every 5 days: about 1.5 gallons each time for a plant 2 feet across, about 1.9 gallons a week. Korean mint, or wrinkled giant hyssop, is a perennial from the mountains of eastern Asia, where it often grows along stream banks. Spikes of showy purple flowers draw bees, butterflies and hummingbirds, and the leaves have a licorice scent that gives it names like blue licorice. Deer and rabbits tend to leave it alone.

PerennialRated for 4 of 6 zones

How often to water Korean mint, month by month

Your city
Plant width
2 ft
Your soil

Type your city above and the days between waterings and the gallons appear here, worked out from your city's climate table. Or read the figures by climate zone further down.

Every month, on your water days. The personal plan prints this for Korean mint and the rest of your yard, on the days your water supplier allows.Get the plan for $19

How this is worked out: established roots fill the top 1 foot of soil, and you water again when that soil has dried halfway. Loam soil holds about 1.5 inches of water per foot. Water the whole area the plant covers, and skip a watering after a good soaking rain.

Which soil do you have?

Dig down a few inches, take a handful of moist soil and squeeze it.

  • Sandy: gritty, falls apart when you open your hand, will not form a ball.
  • Loam: forms a soft ball that crumbles when you poke it.
  • Clay: forms a firm, sticky ball and squeezes out into a ribbon between thumb and finger.

Still not sure? Pick loam. Most garden beds sit between sand and clay.

How to measure plant width

A shrub with its width marked from one side to the other and the circle under it shaded blue

Measure across the plant, from the tips of the leaves on one side to the tips on the other.

Water the whole area the plant covers, shown in blue. The gallons here cover that area.

A wider plant means more gallons each watering, not more waterings. While it is young, measure again each spring.

How to tell it needs water

  • When the soil around Korean mint has dried a few inches down in summer, it is ready for water
  • Flower spikes thinning out in a long hot spell can follow dry soil
  • Lower leaves yellowing in heavy, soggy soil point to too much water
  • Leaves smelling of licorice when brushed is normal, not a sign of stress

How to water it

  • Soak the root zone, then let the upper soil dry before watering again
  • Plant in full sun in soil that drains well
  • Group several plants at the front of a border
  • Cut spent spikes to keep the plant tidy
  • Use it along walkways or in small spaces

Through the seasons

Water new plants regularly until roots settle. Established plants want moderate water through summer bloom, with deep soaks rather than frequent sprinkles. Stems die back in winter and regrow in spring, so water only lightly while it rests. Korean mint gets a moderate water rating from WUCOLS on the north-central coast and the south coast, and in the Central Valley and South Inland. WUCOLS marks it as not suited to the low desert. The high desert has no WUCOLS evaluation for it.

In pots

Korean mint grows well in a large pot near a seat, where you can brush its fragrant leaves. Fill it with a well-drained mix. Water once the upper couple of inches have dried, until it runs from the bottom. In summer, check every few days, since flowering plants in pots dry quickly. Keep the saucer empty. Cut spent spikes to tidy it. In winter, after the stems die back, water only lightly.

1 Your climate zone six WUCOLS zones, each from its own reference city
2.67gal per sq ft in JulyModerate water use in the Central Valley zone
A year
17.11 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.671.32.02.70.4JAN0.65FEB1.09MAR1.52APR2.08MAY2.48JUN2.67JUL2.39AUG1.8SEP1.18OCT0.56NOV0.34DEC0.671.32.02.70.4JFM1.52AMJ2.67JAS1.18OND
Gallons per square foot per month, Central Valley. Peak 2.67 in Jul, 17.11 a year.

Monthly water need by climate zone

Korean Mint: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.78––
Feb0.530.650.810.87––
Mar0.871.091.151.3––
Apr1.181.521.41.61––
May1.462.081.611.95––
Jun1.612.481.742.29––
Jul1.612.671.982.51––
Aug1.492.391.862.33––
Sep1.241.81.491.86––
Oct0.871.181.151.33––
Nov0.470.560.840.9––
Dec0.310.340.650.68––
Year1217.1115.518.41––

How this is worked out: the WUCOLS water rating for each zone times that zone’s climate for the month. A dash means WUCOLS does not rate the plant there. The figures are what the plant uses, before sprinkler losses.

Plants with the same water needs 16

Rated moderate water in the Central Valley, like Korean mint. Plants that drink alike can share one valve and one schedule.

Similar plants that need less water 16

Rated lower than Korean mint in the Central Valley. Worth a look for a new bed or a lawn replacement.

Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes Korean mint, your sprinkler type and the month, and gives the minutes per water day for that supplier's schedule. Or put it in a zone of the personal watering plan and get all twelve months printed.

Questions people ask

How often should I water Korean mint in summer?

In July, established Korean mint in loam needs a deep watering about every 5 days in the Central Valley, about every 7 days on the south coast and about every 6 days in the South Inland zone. Sandy soil holds less water, so waterings come closer together. Clay stretches them. Check the soil before each watering and skip one after a soaking rain.

How much water does Korean mint need per day?

In July in the Central Valley, established Korean mint needs about 0.3 gallons a day for a plant 2 feet across and about 1.1 gallons a day for a plant 4 feet across. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for Korean mint change across California?

Yes. WUCOLS rates Korean mint separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, moderate water in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, not evaluated in the High and Intermediate Desert zone, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Does Korean mint attract pollinators?

Yes, its purple flowers attract bees, butterflies and hummingbirds. It suits pollinator gardens. Plant it in groups.

Do deer eat Korean mint?

It tolerates browsing from deer and rabbits. That suits gardens near wild areas. Pollinators still visit freely.

Why is it called blue licorice?

Its leaves have a licorice scent. Other names include Indian mint and purple giant hyssop. Brush the leaves to smell it.

Where does Korean mint grow wild?

It grows in mountain regions of eastern Asia, especially along stream banks. In gardens it wants full sun and drainage. It fits small spaces well.

Does Korean mint come back each year?

Yes, it is a perennial that dies back in winter and regrows in spring. Water lightly while it rests. Cut old stems in late winter.

More plant watering guides

Sources