WateringTimesWatering plan, $19
Solidago canadensis, WUCOLS IV

How often to water Canada goldenrod in California

In July on the north-central coast, established Canada goldenrod 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. Canada goldenrod is a perennial wildflower native across much of North America, growing 2 to 6 feet tall. From late summer into fall it carries arching, pyramid-shaped plumes of tiny yellow flowers that bees and butterflies crowd. It spreads by rhizomes and wind-borne seed and prefers full sun in soil with some clay that stays moist but not wet.

PerennialRated for 3 of 6 zones

How often to water Canada goldenrod, 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 Canada goldenrod 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 3 inches down in the clump during bloom signals that goldenrod needs a deep soak
  • Lower leaves drying and dropping in a hot spell can indicate the root zone has dried out
  • Orange pustules on leaf undersides point to rust, and a white film to powdery mildew, rather than thirst
  • Yellowing stems in waterlogged soil can indicate overwatering, since it prefers moist but not wet ground
  • New shoots appearing well beyond the clump come from spreading rhizomes, not from extra water

How to water it

  • Water at the base of the stems with drip or a soaker, keeping the leaves dry to limit rust
  • Moisten the root zone about 8 inches deep, then let the top couple of inches dry
  • Plant in full sun in loam or soil with some clay that holds moisture without staying wet
  • Edge the bed, and cut back spent plumes before seed forms to control spread
  • Space clumps for air movement and widen the watered area only as far as you want it to grow

Through the seasons

Keep new plants evenly moist until they root and send up fresh growth. Established clumps take deep watering through summer, especially as flower plumes form in late summer and fall. Stems die back after bloom, and the roots rest through winter. WUCOLS rates Canada goldenrod moderate water on the north-central coast, on the south coast and in South Inland. WUCOLS has not evaluated it for the Central Valley, the high desert or the low desert. Winter rain usually supplies resting clumps on the coast.

In pots

Canada goldenrod can grow in a large container, which keeps its spreading rhizomes in check. Use a loam-based mix and a pot with drainage holes. In summer heat, test the mix with a finger every couple of days and water when the top inch or two is dry. Let excess drain away and tip out the saucer. Cut back spent flower plumes before they shed seed. After the stems die back, water only enough to keep the mix from drying out completely.

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

WUCOLS lists Canada Goldenrod as not evaluated for the Central Valley zone, so no monthly figure is computed here.

Monthly water need by climate zone

Canada Goldenrod: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.37–0.780.78––
Feb0.53–0.810.87––
Mar0.87–1.151.3––
Apr1.18–1.41.61––
May1.46–1.611.95––
Jun1.61–1.742.29––
Jul1.61–1.982.51––
Aug1.49–1.862.33––
Sep1.24–1.491.86––
Oct0.87–1.151.33––
Nov0.47–0.840.9––
Dec0.31–0.650.68––
Year12–15.518.41––

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 not evaluated in the Central Valley, like Canada goldenrod. 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 ratingBig-Flowered FoxgloveDigitalis grandifloranot 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 rating
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes Canada goldenrod, 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 Canada goldenrod in summer?

In July, established Canada goldenrod in loam needs a deep watering 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 Canada goldenrod need per day?

In July on the north-central coast, established Canada goldenrod 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 Canada goldenrod change across California?

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

Does goldenrod cause hay fever?

Goldenrod is often blamed, but it is not related to the ragweed that causes allergy symptoms. Its flowers draw bees and butterflies.

Is Canada goldenrod invasive?

It spreads by seed and rhizomes and is considered weedy by some gardeners. Give it room in a meadow or native garden. Cut plumes before seed forms where spread is a concern.

When does Canada goldenrod bloom?

It flowers from late summer into fall, roughly August to October, after many summer flowers fade. Each arching plume can hold hundreds of tiny yellow flowers.

Can you overwater Canada goldenrod?

Yes. It likes moist soil but not wet ground, and constantly soggy conditions weaken it. Let the surface dry between waterings.

Why are my goldenrod leaves spotted?

Leaf spot, rust and powdery mildew all appear on goldenrod. Water at the soil rather than over the leaves, and give clumps room for air to move.

More plant watering guides

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Sources