WateringTimesWatering plan, $19
Digitalis lutea, WUCOLS IV

How often to water straw foxglove in California

In July in the Central Valley, established straw foxglove 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. Straw foxglove is a clump-forming perennial foxglove from central Europe, about 2 feet tall, with narrow, glossy green leaves. Over a long summer season it sends up dense, leafy spires of small, soft yellow trumpet flowers. It grows in almost any soil except very wet or very dry, and it does best in humus-rich, alkaline soil in part shade.

PerennialRated for 3 of 6 zones

How often to water straw foxglove, 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 straw foxglove 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 an inch or two down around the clump in summer means it needs water, since parched soil does not suit it
  • Leaves yellowing and crowns rotting in soggy ground point to soil that stays too wet
  • A white, powdery film on the leaves points to powdery mildew rather than a watering problem
  • Brown spots scattered on the leaves suggest leaf spot, which more water will not fix
  • Fading main spikes with no side shoots call for deadheading, not extra water

How to water it

  • Water at the base of the clump with drip or a soaker, keeping the leaves dry
  • Soak about 6 inches deep, then let the top inch dry before the next watering
  • Plant in humus-rich soil in part shade, though it also grows in sun or full shade
  • Cut the main flower spike as it fades to bring on flowering side shoots
  • Divide crowded clumps in early spring, and water the divisions well

Through the seasons

Water new plants regularly until they root in. Flower spires open over a long stretch of summer, and cutting the first spike as it fades brings more on side shoots. The clump dies back in winter and regrows in spring. Steady moisture matters most from spring growth through bloom. Winter rain usually covers resting clumps on the coast and in the Central Valley. WUCOLS rates straw foxglove moderate water on the north-central coast, in the Central Valley and in South Inland. WUCOLS has not evaluated it for the south coast. WUCOLS marks it as not suited to the high desert or the low desert.

In pots

Straw foxglove suits a deep container in part shade, where its slim yellow spires stand above the rim. Choose a humus-rich mix that drains freely and a pot with holes in the base. In warm weather, test the mix with a finger every couple of days and water once the top inch dries. Let excess run off, then empty the saucer. Cut faded spikes, and water lightly once growth slows in fall.

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

Straw Foxglove: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.4–0.78––
Feb0.530.65–0.87––
Mar0.871.09–1.3––
Apr1.181.52–1.61––
May1.462.08–1.95––
Jun1.612.48–2.29––
Jul1.612.67–2.51––
Aug1.492.39–2.33––
Sep1.241.8–1.86––
Oct0.871.18–1.33––
Nov0.470.56–0.9––
Dec0.310.34–0.68––
Year1217.11–18.41––

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 straw foxglove. 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 straw foxglove 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 straw foxglove, 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 straw foxglove in summer?

In July, established straw foxglove in loam needs a deep watering about every 5 days in the Central Valley 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 straw foxglove need per day?

In July in the Central Valley, established straw foxglove 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 straw foxglove change across California?

Yes. WUCOLS rates straw foxglove separately for each of the six California climate zones: moderate water in the North-Central Coastal zone, moderate water in the Central Valley zone, not evaluated 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.

Is straw foxglove poisonous?

Yes. All foxgloves, including this one, are toxic if eaten and toxic to pets. Wear gloves when handling it, and keep it away from children's play areas.

Does straw foxglove come back every year?

Yes. It is a clump-forming perennial rather than a biennial, so it returns each spring. Divide it in early spring when it gets crowded.

How do I get more flowers on straw foxglove?

Cut back the main flower spike as it fades. That encourages flowering side shoots and extends the season.

Can straw foxglove grow in shade?

Yes. It does best in part shade and also tolerates full shade or full sun. Keep the soil from drying out in sunnier spots.

Can you overwater straw foxglove?

Yes. Soggy, poorly drained ground is one of the few conditions it will not accept. Let the surface dry between waterings.

More plant watering guides

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Sources