WateringTimesWatering plan, $19
Alcea rosea cvs., WUCOLS IV

How often to water perennial hollyhock in California

In July in the Central Valley, established perennial hollyhock in loam needs a deep watering about every 14 days: about 1.5 gallons each time for a plant 2 feet across, about 0.8 gallons a week. Perennial hollyhock is a tall, short-lived member of the mallow family that sends up stout flower spikes 5 to 8 feet tall. Large cup-shaped blooms in white, pink, red, purple or yellow open from early summer into fall. It likes rich, well-drained soil and water delivered at the roots, since wet leaves invite rust.

PerennialCalifornia nativeRated for 4 of 6 zones

How often to water perennial hollyhock, 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 perennial hollyhock 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

  • Soil dry 2 to 3 inches down at the base of the stalks signals that hollyhock needs a deep soak
  • Lower leaves withering in summer heat is common for hollyhock, so check the soil before assuming thirst
  • Orange or brown pustules on the undersides of leaves point to rust, which spreads on wet foliage
  • Yellowing, collapsing stalks over soggy soil can indicate overwatering or poor drainage
  • Fine webbing and pale stippling on the leaves point to spider mites rather than a watering problem

How to water it

  • Water at the base of the stalks with drip or a soaker hose, keeping the leaves dry to limit rust
  • Moisten the soil about a foot deep, then let the top couple of inches dry before the next watering
  • Water early in the day whenever the leaves do get wet, so they dry quickly
  • Work compost into the bed for rich, well-drained soil, and space plants so air can move
  • Extend the watered area to self-sown seedlings you want to keep, and pull the rest

Through the seasons

Keep new plants evenly moist until they root in. Established clumps take deep soakings from late spring through summer, while the spikes rise and bloom. Plants are short lived but reseed readily, so seedlings often replace older clumps. After flowering, cut the stalks down and reduce water. WUCOLS rates perennial hollyhock low water on the north-central coast and in the Central Valley. It rates moderate water on the south coast and in South Inland. WUCOLS marks it as not suited to the high desert or the low desert. Winter rain usually covers resting plants on the coast and in the Central Valley.

In pots

Hollyhock's tall stalks suit only a deep, heavy pot, and shorter cultivars do best in containers. Use a rich, well-drained mix and a pot with drainage holes. Check the mix 2 inches down every few days in summer heat, watering at the soil rather than over the leaves. Soak until water runs out, then empty the saucer. Set the pot where wind cannot topple the spikes. After flowering, cut back the stalks and water less through winter.

1 Your climate zone six WUCOLS zones, each from its own reference city
1.07gal per sq ft in JulyLow water use in the Central Valley zone
A year
6.84 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.631.31.92.50.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.631.31.92.50.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Perennial Hollyhock: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.780.78––
Feb0.210.260.810.87––
Mar0.350.431.151.3––
Apr0.470.611.41.61––
May0.580.831.611.95––
Jun0.640.991.742.29––
Jul0.641.071.982.51––
Aug0.60.951.862.33––
Sep0.50.721.491.86––
Oct0.350.471.151.33––
Nov0.190.220.840.9––
Dec0.120.140.650.68––
Year4.86.8415.518.41––

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 low water in the Central Valley, like perennial hollyhock. Plants that drink alike can share one valve and one schedule.

AgapanthusAgapanthus orientalislow water, Central Valley1.07 gal/sq ft in JulyGeraniumsPelargonium x hortorum and cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyIrisesIris germanicalow water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyYarrowAchillea millefolium (non-native hybrids)low water, Central Valley1.07 gal/sq ft in JulyMountain AlyssumAlyssum montanumlow water, Central Valley1.07 gal/sq ft in JulySilver SageSalvia argentealow water, Central Valley1.07 gal/sq ft in JulyPurple MulleinVerbascum phoeniceumlow water, Central Valley1.07 gal/sq ft in JulySilvery YarrowAchillea clavennaelow water, Central Valley1.07 gal/sq ft in JulyFern Leaf YarrowAchillea filipendulinalow water, Central Valley1.07 gal/sq ft in JulyCalifornia Native YarrowAchillea millefolium (CA native cultivars)low water, Central Valley1.07 gal/sq ft in JulyWoolly YarrowAchillea tomentosalow water, Central Valley1.07 gal/sq ft in JulyMountain Lady's MantleAlchemilla alpinalow water, Central Valley1.07 gal/sq ft in JulyLady's MantleAlchemilla mollislow water, Central Valley1.07 gal/sq ft in July
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes perennial hollyhock, 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 perennial hollyhock in summer?

In July, established perennial hollyhock in loam needs a deep watering about every 14 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 perennial hollyhock need per day?

In July in the Central Valley, established perennial hollyhock needs about 0.1 gallons a day for a plant 2 feet across and about 0.4 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 perennial hollyhock change across California?

Yes. WUCOLS rates perennial hollyhock separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, moderate water in the South Coastal zone, moderate water in the South Inland zone, not suited to this region 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.

How do I stop rust on hollyhocks?

Water at the base of the plant so the leaves stay dry, since rust spores need moisture to infect. Remove infected leaves as soon as you see them, and space plants for good air circulation. Water early in the day if foliage gets wet.

Why do hollyhock leaves look bad by midsummer?

The large lower leaves often wither in summer heat and draw rust, leaf spot and pests. Strip the worst leaves and keep watering at the roots. Lower plants set in front will hide the bare stems.

Do hollyhocks come back every year?

They are short lived and often behave as biennials, but they reseed readily. Let a few seed heads ripen if you want plants year after year. Water new seedlings until they root in.

Do hollyhocks need staking?

Their rigid spikes usually stand on their own. In windy, exposed spots, a stake can keep the tallest stems upright.

Can you overwater hollyhocks?

Yes. They need well-drained soil, and soggy ground can rot the roots. Frequent overhead sprinkling also feeds rust on the leaves. Soak the soil deeply, then let the top dry.

More plant watering guides

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Sources