WateringTimesWatering plan, $19
Linaria alpina, WUCOLS IV

How often to water alpine toadflax in California

In July on the north-central coast, established alpine toadflax 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. Alpine toadflax is a short-lived perennial from the mountains of central and southern Europe, only a few inches tall. Its trailing stems carry narrow blue-green leaves and, in summer, short spikes of little snapdragon-like flowers in purple with an orange spot. It wants full sun and light, well-drained, moderately fertile soil, so it suits rock gardens, gravel and pots.

PerennialRated for 2 of 6 zones

How often to water alpine toadflax, 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 alpine toadflax 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

  • Gritty soil dry an inch or two down in summer means alpine toadflax can take water
  • Trailing stems wilting in afternoon heat point to a dry root zone
  • Plants fading after two or three years is normal for this short-lived perennial
  • A rotting crown in heavy, wet soil points to poor drainage

How to water it

  • Water lightly when the top inch of gritty soil dries
  • Plant in full sun in light, well-drained soil
  • Grow it in rock gardens, gravel beds, wall pockets or troughs
  • Cut it back after flowering if you do not want seedlings
  • Let a few seeds drop to replace aging plants

Through the seasons

Water new plants regularly until they root in. Established plants want moderate water through summer bloom and sharp drainage at all times. It is short-lived but may self-seed, so a planting can renew itself. Aphids and powdery mildew are the usual problems. WUCOLS rates alpine toadflax moderate water on the north-central coast and in South Inland. WUCOLS marks it as not suited to the Central Valley, and has not evaluated it for the south coast, the high desert or the low desert.

In pots

Alpine toadflax is a natural for small pots, troughs and wall planters. Use a light, gritty, well-drained mix. Water when the top inch dries, until it drains through. In summer, small pots can dry daily, so check often. Never leave the pot standing in water, since the crown rots easily. Trim after bloom to tidy it. In winter, water only when the mix dries, since soggy roots rot.

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

WUCOLS lists Alpine Toadflax as not suited to this region for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Alpine Toadflax: 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 10

Rated not suited to this region in the Central Valley, like alpine toadflax. Plants that drink alike can share one valve and one schedule.

Desert RoseAdenium obesumnot rated, Central Valleyno Central Valley ratingKahili GingerHedychium gardnerianumnot rated, Central Valleyno Central Valley ratingSkunk CabbageLysichiton americanusnot rated, Central Valleyno Central Valley ratingEgyptian Star FlowerPentas lanceolatanot rated, Central Valleyno Central Valley ratingSwedish IvyPlectranthus verticillatusnot rated, Central Valleyno Central Valley ratingSolomon's SealPolygonatum odoratum (japonicum)not rated, Central Valleyno Central Valley ratingPainted DaisyTanacetum coccineum (Pyrethrum roseum)not rated, Central Valleyno Central Valley ratingWandering JewTradescantia fluminensis (SHADE)not rated, Central Valleyno Central Valley ratingMoses-in-the-CradleTradescantia spathacea (Rhoeo spathacea)not rated, Central Valleyno Central Valley ratingHeath-Leafed BanksiaBanksia ericifolianot 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 alpine toadflax, 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 alpine toadflax need per day?

In July on the north-central coast, established alpine toadflax 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 alpine toadflax change across California?

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

Is alpine toadflax perennial?

It is a short-lived perennial. Plants may last only a few years. Self-sown seedlings replace them.

Where should I plant alpine toadflax?

It suits rock gardens, gravel gardens, wall pockets and containers. Give it full sun and light, well-drained soil. Avoid heavy clay.

Does alpine toadflax reseed?

Yes, it can self-seed. Cut plants back after flowering to prevent that. Leave some seed if you want new plants.

What pests bother alpine toadflax?

Aphids and powdery mildew can appear. Keep plants in sun with good air flow. Water the soil, not the leaves.

How tall does alpine toadflax get?

It stays only a few inches tall and spreads into a small trailing mat. It is a tiny plant. Grow it where it will not be crowded.

More plant watering guides

Queen's WreathBeauverd's Widow's-ThrillBird's Eye BushProstrate Natal PlumChenille PlantCopperleafSugar MapleDesert Rose

Sources