How to Grow Kaiser Wilhelm
Wikimedia Commons
Kaiser Wilhelm
Rosa 'Kaiser Wilhelm'
flowerKaiser Wilhelm is a classic hybrid perpetual rose known for its deep crimson-red blooms with a velvety texture and rich fragrance. This vigorous shrub rose produces large, fully double flowers repeatedly throughout the growing season. It's a heritage variety prized by gardeners for its old-fashioned charm and reliable performance.
When should you plant Kaiser Wilhelm in your zone?
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Example Kaiser Wilhelm timeline · Pittsburgh, PA (Zone 6b)
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Plant Kaiser Wilhelm
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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First Kaiser Wilhelm blooms
Mid-to-late summerBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Kaiser Wilhelm dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 5-9, with best performance in zones 6-8
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Bare Root/Transplant
2-4 weeksRecently planted rose with minimal growth, establishing root system in soil
Plant in early spring or fall. Soak bare roots for 12 hours before planting. Keep soil consistently moist but not soggy. Mulch around base, keeping 2 inches away from graft union.
Early Growth
3-6 weeksNew shoots and leaves emerging from canes, plant developing basic structure
Remove any weak or crossing canes. Prune to an open vase shape. Apply balanced fertilizer every 2-3 weeks. Monitor for pests.
Bud Formation
2-3 weeksFlower buds appearing at shoot tips, visible swelling at apex of canes
Continue regular watering and feeding. Deadhead adjacent flowers to direct energy. Apply rose-specific fertilizer with higher phosphorus for blooming.
Flowering
3-4 weeks per flush, repeating through seasonLarge, fully double crimson-red blooms opening, releasing strong fragrance
Deadhead spent flowers just above a 5-leaflet leaf to encourage repeat blooming. Continue watering at soil level, avoiding foliage. Harvest flowers in early morning.
Fall Dormancy
Growth slowing, reduced blooming, foliage may yellow or darken
Reduce fertilizing in late summer. Stop deadheading in fall to allow hips to form and signal dormancy. Perform major pruning in late winter/early spring.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Hand-pick beetles in early morning or shake onto cloth. Use pheromone traps nearby, not directly on rose. Apply neem oil or insecticidal soap. Encourage beneficial insects.
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Spray with strong water stream to dislodge. Apply insecticidal soap or neem oil. Introduce ladybugs or parasitic wasps. Monitor closely on new growth.
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Mist foliage regularly to increase humidity. Spray with neem oil or sulfur in dry conditions. Ensure adequate watering to reduce stress. Release predatory mites.
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Remove infected leaves immediately. Improve air circulation. Water only at soil level, never wetting foliage. Apply fungicide (sulfur or copper) preventatively. Mulch to prevent soil splash.
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Reduce humidity and improve air flow. Spray with sulfur, neem oil, or baking soda solution. Remove infected growth. Space plants adequately.
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No cure; remove and destroy infected plant. Ensure good mite control. Plant resistant varieties nearby.
Uses
Culinary Rose Petals
CulinaryThe fragrant petals can be used in salads, desserts, rose water, and specialty teas, though verify pesticide-free cultivation first. [source]
Cut Flower Arrangements
HouseholdKaiser Wilhelm is prized for formal floral arrangements, wedding bouquets, and as a fragrant cut flower centerpiece due to its large, elegant blooms and strong perfume. [source]
Traditional Rose Remedies
MedicinalHistorically used in herbal medicine and aromatherapy; petals and rose hips contain vitamin C and antioxidants, though modern medicinal use is limited. [source]
Dried Flowers & Potpourri
CraftThe fragrant petals dry beautifully for use in dried arrangements, potpourri, sachets, and craft projects, retaining their deep color and fragrance. [source]
Pollinator Support
WildlifeHybrid perpetual roses provide nectar and pollen for bees, butterflies, and other beneficial insects, supporting garden biodiversity. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Cut flowers in early morning when buds are fully developed but petals just opening for longest vase life (7-10 days). Cut at a 45-degree angle above a 5-leaflet leaf, removing 1/3 to 1/2 of the stem. Recut stems and change water daily. Remove lower foliage from cut stems.
Fun Facts
- 🌱 Kaiser Wilhelm was introduced in 1891 and is named after the German Emperor Wilhelm II, reflecting the rose's German heritage and imperial stature.
- 🌱 As a hybrid perpetual rose, Kaiser Wilhelm revolutionized rose breeding by offering repeat blooming throughout the season, a trait that led to the modern shrub roses we know today.
- 🌱 The deep crimson color and velvety texture of Kaiser Wilhelm petals are due to high anthocyanin concentrations, the same compounds that give red wine and blueberries their color.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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