WateringTimesWatering plan, $19
Nicotiana sylvestris, WUCOLS IV

How often to water flowering tobacco in California

In July in the Central Valley, established flowering tobacco 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. Flowering tobacco is a tender, short-lived perennial in the nightshade family, from northwestern Argentina and Bolivia. A big rosette of coarse, sticky, bright green leaves sends up stems 3 to 5 feet tall. Clusters of fragrant, long-tubed white flowers open from summer into fall. It wants rich soil that drains well, and afternoon shade where summers run hot.

PerennialRated for 4 of 6 zones

How often to water flowering tobacco, 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 flowering tobacco 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 rosette during bloom means flowering tobacco is ready for a soak
  • Large leaves still limp in the morning over dry soil point to thirst, while a brief afternoon droop can be heat alone
  • Gray, fuzzy growth on flowers or leaves is gray mold, which spreads where the plant stays damp and crowded
  • Yellowing lower leaves and a soft base over soggy soil point to overwatering or poor drainage
  • Sticky leaves are normal, since glandular hairs cover them, so stickiness alone does not mean pests or a watering fault

How to water it

  • Water at the base of the rosette with drip or a soaker, keeping water off the leaves and flowers
  • Soak the root zone well, then let the top couple of inches dry before the next watering
  • Work compost into the bed so the soil stays rich and holds moisture while still draining freely
  • Spread mulch around the plant, keeping it clear of the rosette
  • Give the bed afternoon shade in hot inland gardens so the big leaves lose less water

Through the seasons

Water new transplants whenever the top of the root ball dries, until the rosette is growing well. Bloom runs from early summer until frost, so soil checks matter most through that stretch. This short-lived perennial is tender to frost. In mild winters it can resprout from the roots, and it reseeds freely. Winter rain covers the cool months on the coast and in the Central Valley. WUCOLS rates flowering tobacco moderate water on the north-central coast, in the Central Valley and on the south coast. It rates low water in South Inland. WUCOLS has not evaluated it for the high desert or the low desert.

In pots

Flowering tobacco needs a big, heavy container to hold its wide rosette and tall flower stems. Use a rich mix and a pot with open drainage holes. Check the top inch daily in summer heat, since large leaves draw a pot down fast. Water until it runs from the holes, then empty the saucer. Set the pot where it gets afternoon shade. The plant is tender to frost, so move the pot to shelter before freezing nights or treat it as a seasonal plant.

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

Flowering Tobacco: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.370.40.780.31––
Feb0.530.650.810.35––
Mar0.871.091.150.52––
Apr1.181.521.40.64––
May1.462.081.610.78––
Jun1.612.481.740.92––
Jul1.612.671.981––
Aug1.492.391.860.93––
Sep1.241.81.490.74––
Oct0.871.181.150.53––
Nov0.470.560.840.36––
Dec0.310.340.650.27––
Year1217.1115.57.37––

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 flowering tobacco. 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 flowering tobacco 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 flowering tobacco, 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 flowering tobacco in summer?

In July, established flowering tobacco in loam needs a deep watering about every 5 days in the Central Valley, about every 7 days on the south coast and about every 14 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 flowering tobacco need per day?

In July in the Central Valley, established flowering tobacco 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 flowering tobacco change across California?

Yes. WUCOLS rates flowering tobacco 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, low 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 flowering tobacco poisonous?

Yes. It is toxic to people, cats, dogs and horses if eaten. Wear gloves when handling it, since the sticky leaf hairs can irritate sensitive skin.

Will flowering tobacco come back next year?

Sometimes. It is a short-lived perennial that is tender to frost, and in mild winters it can resprout from its roots. It also reseeds readily, so seedlings often take its place.

Can I grow flowering tobacco near tomatoes?

No. Keep it away from tomatoes, potatoes, peppers and eggplant. These relatives can pass tobacco mosaic virus and other diseases back and forth.

How do I keep flowering tobacco blooming?

Remove spent flowers to encourage more. It can bloom from June until the first frost. Check the soil around the rosette through that stretch, and soak it when the top couple of inches are dry.

Does flowering tobacco need sun or shade?

It grows in full sun or part shade. In hot-summer areas, give it shade in the afternoon.

Why is my flowering tobacco falling over?

Its tall, upright habit can need support. Stake the flower stems early in the season, before they lean.

More plant watering guides

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Sources