7 Reasons Your Hellebore Plants Are Not Blooming

Hellebores are long-lived, gracing the garden with their nodding, cupped blooms in late winter and early spring. An elegant surprise in the cool season landscape, they delight in shades from blush to lemon to scarlet and near black. Their handsome palmate foliage in dark green is interesting year-round.

Hellebores are cold hardy and grow across climate zones with ease. They’re worthy of a spot in the woodland border and shady bed where they can spread for impact, slowly colonizing to form a ground cover. They also make lovely container specimens.

Hellebores are mostly problem-free, living for years with reliable performance. However, changes to optimal growing conditions or common pests or fungal problems can hinder flowering. If your hellebore is not blooming, explore a few primary causes to make adjustments for future buds and blooms.

About Hellebores

Hellebores are in the buttercup family, Ranunculaceae, with about 20 species native to Europe and Asia. Helleborus orientalis (Lenten rose) and their hybrids (x hybridus), and the earlier-blooming H. niger (Christmas rose), are long-lived, some reaching 20 years or more. There are those with tall stems, like H. argutifolius (holly-leaved) and H. foetidus, stinking hellebore. 

Heavily hybridized for vigor and bloom density, hellebores boast a long bloom time in rich colors with single or double flowers. Providing optimal growing conditions builds sturdy root systems and boosts overall health and blooming. For a strong foundation, they prefer fertile, loamy, or sandy soils with good drainage.

If your hellebore isn’t blooming, there may be easy adjustments to restore vitality. Look first to primary growing conditions and a few Helleborus-specific preferences.

Insufficient Light

Hellebores prefer a partially shaded garden location, but they benefit from winter light exposure in order to flower. They’re beautiful under a deciduous canopy that allows the sun to infiltrate in winter with leaf drop. In the summer, the leafy canopy protects them with high, open shade or dappled light that keeps them cool and out of intense, scorching rays.

The winter bloomers need sunlight to set buds. As new foliage emerges in spring, it becomes fuller and more dense with some sun exposure. Stemmed species like Corsican may flop in too much shade.

Young Plants

If your lenten roses are young or newly planted, you may not see blooms until they mature. It can take two to three years to see fully budded stems. 

Younger perennials may be settling in, developing strong roots before they’re able to produce multiple blooms. It’s typical not to have any flowers, or just a few, in early seasons.

If your lenten rose was a florist specimen, it was likely forced to bloom at a certain time. Forcing blooms mimics the right conditions for a plant to flower, like warmth after a cooling period. With this energy spent flowering, the transplanted selection needs time to restore. It may take more than one season for flowering time to regulate.

Transplanting at the Wrong Time

If you’ve recently moved the perennials around, it may take time for them to settle in. The best time to transplant hellebores is in summer or fall during dormancy. Moving them just before flowering or while in flower may delay the process until the following season.

If the specimen was freely growing in the landscape, it should rebound quickly. Root-bound hellebores in containers may take longer to recover. Make sure soils are moist and avoid heat waves or dry spells when transplanting.

Hellebores are best left to form spreading clumps and don’t need regular dividing. Topdress with compost in the fall or spring to provide insulation and extra nutrition to existing soils.

Planting Too Deep

Hellebores need their crown level with the soil surface for best growth and flowering. If they’ve settled below the surface or are planted too deeply, you’ll see reduced vigor and flowering.

At planting, situate the crown level with the point it was in the nursery pot. If you know your bed tends to settle, plant it slightly above soil level.

Water Issues

Established hellebores thrive with average seasonal moisture, though they benefit from supplemental water during dry spells. The low-maintenance bloomers are drought tolerant, but a lack of water leads to slowing growth. If your area experiences a hot, dry summer or fall, energy conservation may hinder regular processes. With winter and spring’s moisture and cooling, they’ll likely rebound for future flowering.

Well-draining soils are essential for overall health. Pooling water or overwatering contributes to pests and diseases, and underwatering leads to a halt in growth.

Fluctuations in water cause plants stress and weaken root systems and stems. Repeated drought and flushes of water may result in reduced vigor and flowering. Aim for even water, allowing soils to dry slightly between watering.

Container-grown hellebores dry out quickly in the summer heat. Depending on your climate and pot size, they may need water more regularly than in-ground specimens.

Pests

Pests don’t usually plague hellebores, but common visitors may cause weakness and damage to foliage, stems, and buds. It’s helpful to detect pests early to prevent them from transmitting diseases and depleting energy. Aphids, including the specific hellebore aphid, are worth scouting in addition to growing conditions when a lack of flowers occurs.

Clipping off impacted foliage is a means of control. If you have a history of aphids or other pests on your perennials, trimming their leaves is a means of prevention. Cut off leaves in early winter, limiting insects with a lack of hosts and cold weather. Trimming old leaves before new growth emerges may reduce infestations on fresh leaves and flowers. It also makes way for budding stems to emerge and grow.

Aphids

Aphids are common sap-sucking insects that feed on a variety of plants. They don’t often pose a severe threat, but they can cause stress and leave behind sticky honeydew, leading to black, sooty mold. They’re also vectors for diseases. There are thousands of species of aphids, and hellebores have their own, in addition: Macrosiphum hellebori.

Spray the leaves and stems with a strong stream of water early in the day to displace the insects. A simple horticultural soap or oil like neem rids the plant of more severe infestations, taking care to follow application guidelines as these affect beneficial insects. Grow a diversity of flowering plants to attract beneficial predators that help as a biological control for aphids.

Diseases

Common fungal diseases and viruses impact overall health and the ability to produce blooms. These relate to cultural practices that harbor spores and promote their spread. For hellebores, common diseases include leaf spot and downy mildew. Others to watch for are hellebore black death, botrytis, and root and crown rot.

Remove old leaves if you have a history of disease problems. This may reduce leaf spot and downy mildew in the spring season by minimizing spread and increasing airflow. Remove old leaves on most hellebores as new leaves and flowers emerge to prevent the spread. Keep the leaves on those with stems, like stinking (H. foetidus) and holly-leaved (H. argutifolius), until after flowering.

Leaf Spot

Leaf spot is a common fungal infection that develops on leaf surfaces. Hellebores have their own specific fungus to watch for, Microsphaeropsis hellebori. Brown, dead spots, round and patchy, increase in size and number and spread across leaves and stems, causing them to blacken. As the dead tissue falls away, leaves become ragged, and stems collapse. Spots may also appear on petals and buds, causing wilting and failure to open.

The fungus develops in the warm conditions from spring to fall but is most likely with spring’s new flush of growth. Any species may show signs, though H. niger is highly susceptible.

The brown-black spots crop up when leaves stay wet from prolonged moisture from rain or overhead watering and in damp situations with reduced air circulation.

Cut off diseased leaves and remove any that drop to avoid overwintering for the next season. Destroy or discard the impacted parts away from the garden to prevent spread, keeping them out of the compost pile. Sanitize pruners while moving between plants. An alcohol wipe or a dip in a 70% isopropyl alcohol solution is handy while working.

Downy Mildew

Peronospora pulveracea, or downy mildew, causes grayish-white lesions on leaves and blooms. While it may do no damage, it can lead to death as it spreads and feeds on water within the leaves.

Spores spread on the wind, on infected plants or tools, or by splashing up from the soil via raindrops and irrigation. The spores begin on the leaves and spread, depleting energy and nutrition.

Leaves turn yellow, distort, and drop during severe infections. The fungus spreads quickly, and if left untreated, plants wither and eventually die. Fortunately, powdery mildew is treatable with early detection and doesn’t usually kill hellebores. Handpick and remove the leaves when feasible.

Discard them, keeping them away from the compost pile. For more extensive outbreaks, horticultural oils like neem can treat downy mildew early on. Organic elements in fungicides like copper may be effective. Follow application directions, as these treatments may impact beneficial insects that visit plants for nectar and pollen. Time of day is important in using products effectively. Prune for airflow to prevent the spread of downy mildew.