WateringTimesWatering plan, $19
Digitalis grandiflora, WUCOLS IV

How often to water big-flowered foxglove in California

In July on the north-central coast, established big-flowered foxglove in loam needs a deep watering about every 9 days: about 1.5 gallons each time for a plant 2 feet across, about 1.1 gallons a week. Big-flowered foxglove is a clump-forming perennial with dark, evergreen leaves and upright spires of creamy yellow, tubular flowers in summer. It grows in almost any soil except very wet or very dry. Partial shade and humus-rich, well-drained soil suit it best, and the plant is toxic if eaten.

PerennialRated for 2 of 6 zones

How often to water big-flowered 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 big-flowered 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 2 inches down around the clump signals that big-flowered foxglove needs water
  • Leaves that stay limp into the morning over dry soil can indicate thirst, especially during bloom
  • Flower spikes that wilt at the tips during summer heat warrant a soil check
  • Yellowing leaves and a soft, darkening crown in wet soil can indicate rot from poor drainage
  • White powdery patches on the leaves point to powdery mildew, which water at the roots does not cure

How to water it

  • Water big-flowered foxglove at the base of the clump, keeping the leaves dry
  • Soak the soil 8 to 10 inches deep, then let the top inch or two dry before watering again
  • Plant in humus-rich, well-drained soil, using a raised bed where clay stays wet in winter
  • Mulch around the clump with compost or fine bark, leaving the crown uncovered
  • Widen the watered area as the clump grows and after you divide it in early spring

Through the seasons

Water a new big-flowered foxglove regularly through its first summer until the clump settles in. Established plants need soil checks most from late spring through summer bloom. The dark leaves stay evergreen, so the clump keeps using some water in winter, though cool weather slows it. Cutting the main spike as it fades brings flowering side shoots and extends the season. On the north-central coast, winter rain usually covers the cool months. WUCOLS rates big-flowered foxglove moderate water on the north-central coast and in South Inland. WUCOLS has not evaluated it for the Central Valley or the south coast. It marks this foxglove as not suited to the high desert or the low desert.

In pots

Big-flowered foxglove grows well in a pot of rich, well-drained mix in partial shade. Check the top inch or two every few days in summer heat, and water when it is dry there. Let excess drain out the holes, then empty the saucer, since the crown dislikes sitting wet. Cut the main spike as it fades to encourage side shoots. In winter the evergreen leaves need only light watering, and a pot should never stay soggy after rain.

1 Your climate zone six WUCOLS zones, each from its own reference city
Not ratedWUCOLS does not rate Big-Flowered Foxglove for the Central Valley zone
A year
no figure
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses

WUCOLS lists Big-Flowered Foxglove as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Big-Flowered Foxglove: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37––0.78––
Feb0.53––0.87––
Mar0.87––1.3––
Apr1.18––1.61––
May1.46––1.95––
Jun1.61––2.29––
Jul1.61––2.51––
Aug1.49––2.33––
Sep1.24––1.86––
Oct0.87––1.33––
Nov0.47––0.9––
Dec0.31––0.68––
Year12––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 not evaluated in the Central Valley, like big-flowered foxglove. Plants that drink alike can share one valve and one schedule.

Lilyleaf LadybellsAdenophora liliifolianot rated, Central Valleyno Central Valley ratingArnicaArnica montananot rated, Central Valleyno Central Valley ratingFrilly BergeniaBergenia ciliatanot rated, Central Valleyno Central Valley ratingCabbage on a StickBrighamia insignisnot rated, Central Valleyno Central Valley ratingBasket PlantCallisia fragransnot rated, Central Valleyno Central Valley ratingForest SedgeCarex sylvaticanot rated, Central Valleyno Central Valley ratingUmbrella DracaenaDianella ensifolianot rated, Central Valleyno Central Valley ratingRusty FoxgloveDigitalis ferrugineanot rated, Central Valleyno Central Valley ratingWoolly FoxgloveDigitalis lanatanot rated, Central Valleyno Central Valley ratingSunset FoxgloveDigitalis obscuranot rated, Central Valleyno Central Valley ratingMale FernDryopteris filix-masnot rated, Central Valleyno Central Valley ratingAlpine Sea HollyEryngium alpinumnot rated, Central Valleyno Central Valley ratingPurple SpurgeEuphorbia dulcisnot rated, Central Valleyno Central Valley ratingQueen of the MeadowFilipendula ulmarianot rated, Central Valleyno Central Valley ratingDropwortFilipendula vulgaris (Filipendula hexapetala)not rated, Central Valleyno Central Valley ratingGentianGentiana scabra procumbensnot rated, Central Valleyno Central Valley rating
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes big-flowered 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 much water does big-flowered foxglove need per day?

In July on the north-central coast, established big-flowered foxglove needs about 0.2 gallons a day for a plant 2 feet across and about 0.7 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 big-flowered foxglove change across California?

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

Yes. It is toxic if eaten, to people and to pets. Wear gloves when handling it and plant it away from areas where children play.

Should I deadhead big-flowered foxglove?

Cut the main spike back as it fades. That encourages flowering side shoots and keeps the plant tidy. Keep checking the soil while this second round of flowers opens.

Can big-flowered foxglove grow in full sun?

It grows in sun or shade, but partial shade suits it best. In full sun the soil dries faster, so check moisture more often through summer.

Can I divide big-flowered foxglove?

Yes. It is a clump-forming perennial that can be divided in early spring. Water the divisions well and keep them evenly moist until new roots take hold.

Can you overwater big-flowered foxglove?

Yes. Very wet soil is one of the few conditions it will not take. Soggy ground around the crown invites rot, so let the top inch or two dry between soakings.

Why are there spots on my foxglove leaves?

Leaf spot, powdery mildew and downy mildew all affect this foxglove. Water at the base so the leaves stay dry, which discourages leaf spot and downy mildew. Aphids are another common problem.

More plant watering guides

NeemFrilly BergeniaBismarck PalmCabbage on a StickBasket PlantForest SedgeAmerican HornbeamJapanese Hornbeam

Sources