Summerific® Holy Grail Hardy Hibiscus

Hibiscus x 'Holy Grail' PP31,478

Proven Winners®

Massive 8-9 Inch Deep Red Blooms Against Near-Black Foliage Create Stunning Garden Drama
Cold Hardy: Thrives in Zones 4-9
Grows 4-5 ft Tall and Wide
Pollinator-Friendly Shrub
Moderate-Growing in Full Sun to Partial Shade

$52⁴³

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Plant Size

Product variants

Planting & Care

Where to Plant

Sunlight: Provide at least 6 hours of direct sunlight per day to maintain the intense, near-black foliage color and ensure sturdy, upright stems. If planted in too much shade, the leaves will fade to green and flower production will decrease significantly.
Soil: This plant craves rich, consistent moisture, making it a great choice for low spots or wet areas where other plants might rot. If you have sandy or fast-draining soil, amend it heavily with compost or peat moss to help hold the necessary water.

Watering Requirements

Keep the soil consistently moist during the first growing season to help the root system establish. Even when mature, this "swamp mallow" has low drought tolerance; inconsistent watering can cause the plant to drop its flower buds before they open.

Pruning Tips

Hardy hibiscus blooms on new wood that shoots up from the base every year, so you should cut all old stems down to about 3 to 6 inches above the ground in early spring. Be patient with this process, as these plants are notoriously late to break dormancy and often won't show signs of life until late May or early June.

Fertilizer Needs

Apply a balanced, slow-release fertilizer or a water-soluble plant food in late spring once you see new growth emerging. Avoid high-nitrogen fertilizers late in the summer, as this can push soft, leafy growth that won't have time to harden off before the first frost.

Delivery and Shipping

Preorder Shipping Schedule

We ship your plants when it's safe to transport them to your zone. Dates are estimated and subject to weather delays.

Zone 3-4	Week of March 30th
Zone 5	Week of March 16th
Zone 6-12	Week of March 2nd

Shipping Rates

Ships in 7-10 business days • Tracking provided • Weather protected

Under $50	$9.99
$50 - $99.99	$14.99
$100 - $149.99	$16.99
$150 - $198.99	$24.99
$199+	FREE

✓ Zone-specific timing • ✓ Professional packaging • ✓ Health guarantee

Understanding Our Container Sizes

At Nature Hills, our plants are sold in industry-standard nursery containers. You will notice we use the word "container" rather than "gallon." Container numbers follow a nursery trade size standard, not liquid volume. The number tells you the plant's size category and general maturity level. A larger container means a more established plant with a stronger root system.

Container Sizes

Quart

Plant age: 6 months to 1 year
Best for: Ground covers, perennials, ornamental grasses
What to expect: Our smallest and most affordable size. Well-suited for planting in multiples across a large area. Allow 1 to 2 seasons for full establishment.

#1 Container

Plant age: 1 to 2 years
Best for: Shrubs, perennials, smaller trees
What to expect: About the size of a large coffee can. A well-developed root system in a manageable size. Good value choice when you have time to let the plant grow into the space over a season or two.

#2 Container

Plant age: 2 to 3 years
Best for: Shrubs and trees where you want faster establishment
What to expect: A noticeable step up from a #1 in both plant size and root development. Good choice when you want visible presence without going to a larger size.

#3 Container

Plant age: 3 to 4 years
Best for: Most plants, most situations — flowering trees, shade trees, evergreen shrubs
What to expect: Our most popular size. Strong, developed root system. Plants in a #3 container make an immediate visual impact from day one. If you want a head start rather than waiting seasons for a plant to fill in, this is typically the right choice.

#5 Container and Larger

Plant age: 4 to 5+ years
Best for: Specimen plants, privacy screens, maximum instant impact
What to expect: Large, mature plants ready to make an immediate statement in your landscape. We also carry #7 and larger sizes for select varieties.

Why "Container" and Not "Gallon"?

Nursery container sizes follow an industry trade standard established for the nursery and horticulture industry. The number is a size designation, not a measurement of liquid volume. Actual soil volume varies by plant type, root mass, and growing medium. Using "container" is the accurate industry term. When you see #1, #2, or #3, think of it as the plant's size tier, not a gallon measurement.

Root Pouch Containers

Some Nature Hills plants arrive in a Root Pouch, a breathable fabric container made from 100% recycled materials. Root Pouches encourage denser root development through air pruning, which discourages root circling and promotes a stronger, more fibrous root ball at the time of planting.

Plants growing in Root Pouch fabric containers, showing the breathable woven fabric construction

There are two types. Knowing which one you have changes how you plant:

Degradable (brown or tan fabric): Plant the entire pouch directly in the ground. The fabric breaks down naturally in the soil over time.
Non-degradable (black or gray fabric): Remove the pouch before planting. Cut the bottom open with scissors, then peel the sides away. The fibrous root ball will hold its shape.

Not sure which type you have? Check the tag on your plant or contact us and we will confirm.

Full Root Pouch planting guide

Choosing the Right Size

Size	Plant Age	Best For
Quart	6 mo to 1 yr	Ground covers, perennials, grasses. Budget-friendly for mass plantings.
#1 Container	1 to 2 yrs	Shrubs, perennials, small trees. Value choice for patient gardeners.
#2 Container	2 to 3 yrs	Shrubs and trees where you want faster establishment.
#3 Container	3 to 4 yrs	Most plants. Immediate visual impact. Our most popular size.
#5 and larger	4+ yrs	Specimen plants, privacy screens, maximum instant impact.

Still not sure which size is right for your project? Our plant specialists are happy to help. Contact us and we will point you in the right direction.

Photo courtesy of Proven Winners - www.provenwinners.com

Proven Winners® Summerific® Holy Grail Hardy Hibiscus

The Proven Winners® Summerific® Holy Grail Hardy Hibiscus USPP31478 (Hibiscus x 'Holy Grail') is a spectacular, cold-hardy ornamental perennial that delivers massive, deep red blooms against rich, near-black foliage, creating a breathtaking contrast in any garden. This show-stopping Hibiscus produces 8-9 inch flowers from midsummer to early fall, ensuring your landscape is bursting with tropical color for months.

Perfect for pollinator gardens, borders, and containers, this low-maintenance, deer-resistant Hibiscus thrives in full sun and loves warm, sunny locations. With its compact, bushy growth habit, Proven Winners® Summerific® Holy Grail Hardy Hibiscus makes an unforgettable focal point in any garden design.

Key Features of Summerific® Holy Grail Hardy Hibiscus

Massive Deep Red Blooms – Stunning 8-9 inch flowers cover the plant all summer.
Dark Burgundy-Black Foliage – A bold contrast against the vivid red blooms.
Long Blooming Season – Enjoy continuous flowers from midsummer through early fall.
Cold Hardy Perennial – Returns year after year in USDA zones 4-9.
Pollinator-Friendly – A top choice for hummingbirds, butterflies, and bees.
Heat & Humidity Tolerant – Thrives in hot summer conditions.
Compact & Bushy Habit – Grows 4-5 feet tall and wide, ideal for landscapes and large containers.
Deer & Rabbit Resistant – Foliage naturally repels browsing animals.
Low Maintenance & Easy to Grow – Drought-tolerant once established.

Landscaping With The Summerific® Holy Grail Hardy Hibiscus

With its dramatic foliage and giant flowers, this Proven Winners® Hardy Hibiscus is an incredible addition to any garden. Use it to:

Create a Stunning Garden Focal Point – Bold red flowers and dark foliage make a dramatic impact.
Enhance Pollinator Gardens – A must-have for attracting hummingbirds, butterflies, and bees.
Add a Tropical Touch to Mixed Borders – Complements plants like Coneflowers, Black-Eyed Susans, and Ornamental Grasses.
Frame Walkways & Foundation Plantings – Compact growth makes it perfect for sunny garden beds.
Make a Statement in Large Containers – Grows beautifully in big pots for patios and balconies.
Use in Mass Plantings for a Lush Effect – Create a wall of color and foliage for a breathtaking display.

Growing & Care Tips

Hardy Hibiscus are very easy to grow despite their tropical appearance!

Sunlight: Thrives in full sun (at least 6+ hours daily).
Soil: Prefers moist, well-drained soil but adapts to a variety of conditions.
Mulch: Top-dress the area with 3-4 inches of arborist bark chips to keep soil moisture consistent.
Water Needs: Moderate to high; keep soil evenly moist during the growing season.
Pruning: Cut back stems to the ground in late fall or early spring for healthy regrowth.
Spacing: Plant 4 feet apart for the best coverage and airflow.

Order Proven Winners® Summerific® Holy Grail Hardy Hibiscus!

If you're searching for a jaw-dropping Hibiscus with bold red blooms and dark foliage, Proven Winners® Summerific® Holy Grail Hardy Hibiscus is the perfect choice! With massive flowers, pollinator-friendly appeal, and easy-care maintenance, this perennial is sure to be a garden highlight.

Order today and enjoy the breathtaking beauty of this incredible Rose Mallow variety in your landscape!

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Growing Zones 4-9

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Frequently Asked Questions

What USDA hardiness zones is Summerific® Holy Grail Hardy Hibiscus suitable for?

Summerific® Holy Grail Hardy Hibiscus is cold hardy in USDA zones 4-9. This perennial will reliably return each spring in these zones, producing massive 8-9 inch blooms from midsummer through early fall. Plant in full sun for best flowering performance.

What is the mature size (height and width) of Summerific® Holy Grail Hardy Hibiscus?

Summerific® Holy Grail Hardy Hibiscus reaches 4-5 feet tall and 4-5 feet wide at maturity. This compact, bushy perennial fits perfectly in borders or large containers without overwhelming smaller plants. Give it adequate space to showcase its dramatic red blooms and dark foliage when you shop at Nature Hills.

Does Summerific® Holy Grail Hardy Hibiscus bloom the first year after planting?

Yes, Summerific® Holy Grail Hardy Hibiscus typically blooms in its first year after planting. You can expect those spectacular 8-9 inch deep red flowers to appear from midsummer through early fall, even on newly planted specimens. Plant in full sun and keep consistently watered the first season for best bloom production.

What are the sunlight requirements for Summerific® Holy Grail Hardy Hibiscus?

Summerific® Holy Grail Hardy Hibiscus requires full sun for optimal blooming and thrives in warm, sunny locations. This heat-tolerant perennial needs at least 6-8 hours of direct sunlight daily to produce its spectacular 8-9 inch red blooms. Plant in your garden's sunniest spot for the best flower production and healthiest growth.

What type of soil does Summerific® Holy Grail Hardy Hibiscus prefer?

Summerific® Holy Grail Hardy Hibiscus thrives in well-draining, fertile soil with consistent moisture. This hardy perennial adapts to various soil types but performs best in rich, organic matter-amended ground. Ensure good drainage to prevent root rot, and shop at Nature Hills for healthy plants ready to establish in your garden.

How much water does Summerific® Holy Grail Hardy Hibiscus need, and is it drought tolerant?

Summerific® Holy Grail Hardy Hibiscus is drought-tolerant once established, typically after its first growing season. During establishment, provide regular watering to keep soil consistently moist but not waterlogged. Once mature, it handles dry periods well but performs best with weekly deep watering during hot summer months.

Should I deadhead Summerific® Holy Grail Hardy Hibiscus, and is it necessary?

Deadheading isn't necessary for Summerific® Holy Grail Hardy Hibiscus to maintain its continuous midsummer to early fall bloom cycle. The plant naturally produces new 8-9 inch flowers throughout the season without intervention. You can remove spent blooms for tidier appearance, but focus your energy on other garden tasks instead.

Will Summerific® Holy Grail Hardy Hibiscus survive shipping damage or arrive healthy?

This hardy perennial is exceptionally resilient and handles shipping stress well due to its robust nature. The plant's natural heat and humidity tolerance, plus its ability to thrive in USDA zones 4-9, means it recovers quickly from transport. Plant immediately upon arrival and water thoroughly to help it establish.

How do I prune or cut back Summerific® Holy Grail Hardy Hibiscus in spring?

Cut Hardy Hibiscus stems down to 4-6 inches above ground level in early spring before new growth begins. In zones 4-6, wait until after the last frost date since stems provide winter protection. Make clean cuts just above outward-facing buds to encourage the plant's naturally compact, bushy habit.