What Grows in Flower Hill, Maryland

USDA Zones 7b · 1K acres

Flower Hill, Maryland, sits in USDA hardiness zone 7b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.

Reliable performers under these conditions include cabbage, prickly pear, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.

Score your parcel · free

Even in Flower Hill, no two yards are alike.

A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Flower Hill lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.

We read public map data around Flower Hill — soil, climate, flood, and parcel records. How we handle your address.

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Flower Hill — the short answer

Flower Hill, Maryland: USDA zone 7b, about 225 days between hard freezes, across 1K acres of town.

USDA zone
7b
USDA PHZM 2023
Last hard freeze (28°F)
Mar 30
NOAA 1991–2020 Climate Normals, 28°F — this town
First hard freeze (28°F)
Nov 10
NOAA 1991–2020 Climate Normals, 28°F — this town
Days between freezes
~225
NOAA 1991–2020 Climate Normals, 28°F — this town
Town area
1K acres
US Census TIGER/Line 2025

Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.

Hardiness Zone Range

7b7b
3a (Cold)13b (Hot)

Zone 7b is Flower Hill's average, not your lot's — a low corner or a tree line moves it. Against Flower Hill's 225-day season, see what your own ground reads.

Soil varies lot by lot — soil types explained.

What this means for growing in Flower Hill

Each reading below is measured for Flower Hill itself — here is what it means for a garden here, and the move an experienced grower makes about it.

Season length

Measured

Flower Hill runs about 225 days between hard freezes — a long growing season.

There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.

Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.

NOAA 1991–2020 Climate Normals

Winter hardiness

Measured

Flower Hill sits in USDA hardiness zone 7b.

The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.

Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.

USDA PHZM 2023

The kind of country Flower Hill is in

Flower Hill sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Flower Hill's own centroid rather than borrowed from Montgomery County.

What that means for soil

What Grows in Flower Hill

Every plant below cleared Flower Hill's own zone 7b and its 225-day season. Each card opens that plant's Maryland profile. How we score.

cabbage, photograph
Growing cabbage in MarylandZones 2–11Flower Hill's 7b — 5 zones of cold margin.
prickly pear, photograph
Maryland prickly pear guideZones 5–10Flower Hill's 7b — 2 zones of cold margin.
California poppy, photograph
California poppy in MarylandZones 6–10Flower Hill's 7b — 1 zone of cold margin.
collard greens, photograph
Collard greens: Maryland growing notesZones 2–11Flower Hill's 7b — 5 zones of cold margin.
fig, photograph
Growing fig in MarylandZones 6–10Flower Hill's 7b — 1 zone of cold margin.
lavender, photograph
Maryland lavender guideZones 5–8Flower Hill's 7b — 2 zones of cold margin.
garlic, photograph
Garlic in MarylandZones 2–10Flower Hill's 7b — 5 zones of cold margin.
grape, photograph
Grape: Maryland growing notesZones 6–9Flower Hill's 7b — 1 zone of cold margin.
Turkish rocket, photograph
Growing turkish rocket in MarylandFlower Hill's 225 days clear the ~90 it needs.
kale, photograph
Maryland kale guideZones 2–11Flower Hill's 7b — 5 zones of cold margin.
hazelnut, photograph
Hazelnut in MarylandZones 4–9Flower Hill's 7b — 3 zones of cold margin.
lentil, photograph
Lentil: Maryland growing notesZones 2–11Flower Hill's 225 days clear the ~70 it needs.
pawpaw, photograph
Growing pawpaw in MarylandZones 5–9Flower Hill's 7b — 2 zones of cold margin.
okra, photograph
Maryland okra guideZones 2–12Flower Hill's 225 days clear the ~50 it needs.
potato, photograph
Potato in MarylandZones 2–11Flower Hill's 7b — 5 zones of cold margin.
iris, photograph
Iris: Maryland growing notesZones 3–10Flower Hill's 7b — 4 zones of cold margin.
sunflower, photograph
Growing sunflower in MarylandZones 2–11Flower Hill's 225 days clear the ~70 it needs.
Apache plume, photograph
Maryland apache plume guideZones 5–11Flower Hill's 7b — 2 zones of cold margin.
hops, photograph
Hops in MarylandZones 3–8Flower Hill's 7b — 4 zones of cold margin.
hosta, photograph
Hosta: Maryland growing notesZones 3–8Flower Hill's 7b — 4 zones of cold margin.
French marigold, photograph
Growing french marigold in MarylandFlower Hill's 225 days clear the ~50 it needs.
holly, photograph
Maryland holly guideZones 5–11Flower Hill's 7b — 2 zones of cold margin.
Virginia creeper, photograph
Virginia creeper in MarylandZones 3–9Flower Hill's 7b — 4 zones of cold margin.
tulip, photograph
Tulip: Maryland growing notesZones 6–8Flower Hill's 7b — 1 zone of cold margin.
Douglas fir, photograph
Growing douglas fir in MarylandZones 4–10Flower Hill's 7b — 3 zones of cold margin.
Ethiopian mustard, photograph
Maryland ethiopian mustard guideZones 4–10Flower Hill's 7b — 3 zones of cold margin.
Kentucky bluegrass, botanical illustration
Kentucky bluegrass in MarylandZones 2–7Flower Hill's 7b — 5 zones of cold margin.
western red cedar, photograph
Western red cedar: Maryland growing notesZones 4–10Flower Hill's 7b — 3 zones of cold margin.
Japanese millet, photograph
Growing japanese millet in MarylandZones 5–10Flower Hill's 225 days clear the ~45 it needs.
ajuga, photograph
Maryland ajuga guideZones 5–11Flower Hill's 7b — 2 zones of cold margin.

Is it too late to plant in Flower Hill?

Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 10 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.

Documented around Flower Hill

Spotted lanternfly documented 1 miles from Flower Hill, first recorded 2022. What to watch for.

What's on the federal record near Flower Hill

Closest first, within ~10 miles of Flower Hill. Listing isn't leaking, and distance isn't exposure.

  1. STRAWBERRY KNOLLS ESBrownfields · 1400 ft
  2. GAITHERSBURG - CONTROLSuperfund · 2600 ft
  3. PMG CO26Underground Storage Tanks · 0.6 mi
  4. YELLOW BAG CLEANERSBrownfields · 0.6 mi
  5. SUNBELT RENTALSBrownfields · 0.6 mi
  6. Montgomery County Multi-Agency Service Park (MASP)Underground Storage Tanks · 0.7 mi
  7. WHETSTONE ELEMENTARY SCHOOLBrownfields · 0.7 mi
  8. NATIONAL COATINGS - SUPPLIES - GAITHERSBURGBrownfields · 0.8 mi
  9. Browning Ferris Inc.Underground Storage Tanks · 0.8 mi
  10. Metropolitan Fleet Service, Inc.Underground Storage Tanks · 0.8 mi
  11. C&C INDUSTRIESBrownfields · 0.8 mi
  12. METRO RENTALS INCBrownfields · 0.8 mi

6 more sites are on the record inside the same radius. See them on the map

Measured from Flower Hill's center, not your beds. Run your own address for what's upwind of you specifically.

Environmental Intelligence

The counts behind that headline — every source type on the record near Flower Hill.

Total Sites

1,631

within ~10 miles of Flower Hill

Risk Level

Elevated

Highest-severity

8 Superfund sites (none NPL-listed)

Severity Distribution

within ~10 miles of Flower Hill

High1Moderate332Low1,298

Highest-Severity Sites

City of Rockville
PFAS Sampling · PFAS Detected
20036 Airpark Exxon
Underground Storage Tanks · Open UST(S)
22800 Courthouse Exxon
Underground Storage Tanks · Open UST(S)
25431 Aspen Hill Exxon
Underground Storage Tanks · Open UST(S)
25474 Kentlands Exxon
Underground Storage Tanks · Open UST(S)

Know Before You Grow

  • Near a brownfield, raised beds of imported soil give your food clean ground.
  • Underground tanks leak petroleum as they age — near a former filling station, test the soil.
  • On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Free Report

Check your specific parcel in Flower Hill

Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.

25+ data sources read at your address, not the Flower Hill average

Your land is one point inside Flower Hill

Everything above resolves to Flower Hill as a whole — one PHZM band and one 28°F frost record, read across 1K acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.

Your Lot vs the Flower Hill Average

Flower Hill Average

  • USDA Zones 7b, averaged across Flower Hill
  • One soil character for all of Flower Hill
  • Frost dates read at Flower Hill's scale: Mar 30 to Nov 10

YOUR Parcel

  • Your exact zone, not Flower Hill's 7b
  • Your SSURGO soil type & pH
  • Your sun exposure, cast in 3D

See MY Growing Report

Free Report

Read your specific parcel in Flower Hill

Pull a site-specific report for your exact address in Flower Hill, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.

Three things about your lot that Flower Hill averages can't show:

Your soil pHYour frost-free days — Flower Hill averages 225Your sun & shade

We read public map data around Flower Hill — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the Flower Hill average

How we know this about Flower Hill

The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Flower Hill’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.

Common questions about Flower Hill

When does frost risk typically end in Flower Hill?

The last hard freeze (28°F) in Flower Hill typically lands around Mar 30, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Apr 20.

When is the first frost in Flower Hill?

The first hard freeze (28°F) in Flower Hill typically arrives around Nov 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 27, so the watching starts about Oct 11 — about 225 days after the spring freeze cleared.

How long is the growing season in Flower Hill?

Measured between 28°F hard freezes, Flower Hill sees about 225 frost-free days — roughly Mar 30 through Nov 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 20 to Oct 27, about 190 days.

Is the soil safe to grow vegetables in Flower Hill?

The federal record around Flower Hill is a meaningful one — 1,631 documented sites, mostly Brownfields entries (762), the nearest Brownfields record about 0.3 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.

How do I protect my plants from frost in Flower Hill?

From about Oct 11 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Nov 10 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Nov 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.

Everything above is measured at Flower Hill's scale — its 7b band and its 225-day season. Your yard writes its own version of Flower Hill's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.

What this page reads at Flower Hill’s own scale

7 of the readings below were taken at Flower Hill's own scale — its own ~225-day season between 28°F freezes, the 1,340 acres it covers and 1,631 documented sites around it; 4 are borrowed from a wider read, named and linked below.

Measured here

  • Flower Hill's own USDA hardiness band, zones 7bUSDA PHZM 2023
  • Flower Hill's own 28°F hard-freeze dates, about Mar 30 and Nov 10 and the ~225-day span between themNOAA 1991–2020 Climate Normals
  • 1,631 documented contamination sites on the federal record near Flower Hill, the closest Brownfields record about 0.3 miles out from the town centreFederal environmental registers
  • Flower Hill's boundary and the 1,340 acres inside itUS Census TIGER/Line 2025
  • Which of 1,086 plants clear zones 7b and a ~225-day seasonGrowable Ground crop-matching engine
  • The ecoregion at Flower Hill's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
  • A documented spotted-lanternfly record within reach of Flower Hilllydemapr (De Bona & Helmus), 10 km survey lattice

Inherited from a wider read

  • Soil character — no town-scale survey exists, so Flower Hill's 1,340 acres read through its county's SSURGO summaryfrom Montgomery County
  • Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Montgomery County
  • The growing challenges every Maryland grower plans around — written at state scale, so they stay on the state guidefrom Maryland
  • Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Montgomery County

What this page can’t tell you

  • The soil pH, drainage, sun hours, and frost pockets on any one lot among Flower Hill's 1,340 acreswhy one lot differs from the next
  • Which side of Flower Hill you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,340 acresreading your own microclimate
  • How close that record sits to YOUR lot — the closest Brownfields record about 0.3 miles out, measured from the town centrehow we read the record
  • Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Flower Hill-wide figureread your own land
The next step finer is your own address