WateringTimesWatering plan, $19
Verbascum undulatum, WUCOLS IV

How often to water wavy-leafed mullein in California

In July in the Central Valley, established wavy-leafed mullein 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. Wavy-leafed mullein is a short-lived evergreen perennial from the Balkans and Greece, grown mostly for its foliage. Its lobed leaves have wavy edges and a dense coat of golden yellow hairs. Branching rosettes send up stems of yellow flowers in summer. It wants full sun, sharp drainage and steady moderate water, never soggy soil.

PerennialRated for 3 of 6 zones

How often to water wavy-leafed mullein, 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 wavy-leafed mullein 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 beside the rosette means it is time for a deep watering
  • Leaves that soften and droop in afternoon heat while the soil below is dry point to thirst
  • Rosettes that yellow and collapse in soil that stays wet point to poor drainage, which mulleins do not tolerate
  • Fine pale speckling on leaves in hot weather points to spider mites, a common mullein pest in hot areas
  • Powdery white patches or dark leaf spots point to fungal disease rather than a lack of water

How to water it

  • Water the soil beside the rosette, keeping water off the hairy leaves
  • Soak until the root zone is wet several inches down, then let the top few inches dry before the next watering
  • Plant in full sun in soil that drains fast, and never where water stands after rain
  • Skip rich amendments and heavy feeding, since mulleins in rich soil grow weak, sprawling stems
  • Use a thin gravel or fine mulch layer around the plant, kept clear of the crown, and widen the watered area as rosettes branch

Through the seasons

Water a new plant regularly through its first summer so its roots reach down into the soil. Established plants still want moderate water through the warm months, with each watering allowed to drain and the top few inches allowed to dry. The rosettes stay evergreen, and flower stems rise in summer. It is short-lived, so plan on replacing plants over time. WUCOLS rates wavy-leafed mullein moderate water on the north-central coast, in the Central Valley and on the south coast. Winter rain covers the cool months in those regions, so water only during long dry spells. WUCOLS has not evaluated it for South Inland, the high desert or the low desert.

In pots

Wavy-leafed mullein can live in a pot if the mix drains freely. Use a gritty mix and a container with large drainage holes. Check the mix 2 inches down every few days in summer, and more often in Central Valley heat. Water until it drains from the holes, then empty the saucer at once so the roots never sit in water. Set the pot in full sun. It is cold hardy to about 20 degrees F, so in winter water only when the mix is dry and rain has not done it.

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

Wavy-Leafed Mullein: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.78–––
Feb0.530.650.81–––
Mar0.871.091.15–––
Apr1.181.521.4–––
May1.462.081.61–––
Jun1.612.481.74–––
Jul1.612.671.98–––
Aug1.492.391.86–––
Sep1.241.81.49–––
Oct0.871.181.15–––
Nov0.470.560.84–––
Dec0.310.340.65–––
Year1217.1115.5–––

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 wavy-leafed mullein. Plants that drink alike can share one valve and one schedule.

DahliasDahlia spp.moderate water, Central Valley2.67 gal/sq ft in JulyFernsNephrolepis cordifolia (SHADE IN DESERT)moderate water, Central Valley2.67 gal/sq ft in JulyDayliliesHemerocallis spp. & cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBegoniasBegonia & ssp. & cvs. (shade in the desert)moderate water, Central Valley2.67 gal/sq ft in JulyCalla LiliesZantedeschia aethiopica SHADE IN DESERTmoderate water, Central Valley2.67 gal/sq ft in JulySageSalvia officinalis and cvs.moderate water, Central Valley2.67 gal/sq ft in JulyBicolor MonkshoodAconitum cammarummoderate water, Central Valley2.67 gal/sq ft in JulyGarden MonkshoodAconitum napellusmoderate water, Central Valley2.67 gal/sq ft in JulyCarpet BugleAjuga reptans (shade)moderate water, Central Valley2.67 gal/sq ft in JulySnowdrop WindflowerAnemone sylvestrismoderate water, Central Valley2.67 gal/sq ft in JulyMountain SandwortArenaria montanamoderate water, Central Valley2.67 gal/sq ft in JulySwamp MilkweedAsclepias incarnatamoderate water, Central Valley2.67 gal/sq ft in JulyOrange MilkweedAsclepias tuberosamoderate water, Central Valley2.67 gal/sq ft in JulyGreater MasterwortAstrantia majormoderate water, Central Valley2.67 gal/sq ft in JulyHardy BegoniaBegonia grandismoderate water, Central Valley2.67 gal/sq ft in JulyWax BegoniaBegonia semperflorensmoderate water, Central Valley2.67 gal/sq ft in July

Similar plants that need less water 16

Rated lower than wavy-leafed mullein in the Central Valley. Worth a look for a new bed or a lawn replacement.

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 JulyPerennial HollyhockAlcea rosea cvs.low water, Central Valley1.07 gal/sq ft in JulyMountain Lady's MantleAlchemilla alpinalow 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 wavy-leafed mullein, 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 wavy-leafed mullein in summer?

In July, established wavy-leafed mullein in loam needs a deep watering about every 5 days in the Central Valley and about every 7 days on the south coast. 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 wavy-leafed mullein need per day?

In July in the Central Valley, established wavy-leafed mullein 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 wavy-leafed mullein change across California?

Yes. WUCOLS rates wavy-leafed mullein 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, not evaluated in the South Inland zone, not evaluated in the High and Intermediate Desert zone, not evaluated in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Why are wavy-leafed mullein leaves golden?

The leaves are densely covered with golden yellow hairs, which give the plant its glow. The name comes from the wavy, undulating leaf margins. The foliage is the main reason to grow it.

Should I cut off the flower stems?

Growers advise cutting them off. This plant is grown for its leaves, and removing the stems keeps it in its leafy rosette stage. The flowers are yellow, about an inch wide, on unbranched stems in summer.

How long does wavy-leafed mullein live?

It is a short-lived perennial, so plan on replacing plants over time. Give it full sun and fast drainage so it lives out its natural span.

What soil does wavy-leafed mullein need?

Soil that drains well is essential, and it should never sit in standing water. Mulleins grow best in lean soil. Rich soil leads to weak, sprawling stems that flop.

Is wavy-leafed mullein frost hardy?

It is cold hardy to at least 20 degrees F. The rosettes stay evergreen through winter. In a colder spell, protect it or treat it as replaceable.

Where does wavy-leafed mullein come from?

It is native to the northwest Balkan Peninsula, Albania and Greece. It grows as a branching, evergreen plant about 1 to 3 feet tall and 1 to 2 feet wide.

More plant watering guides

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Sources