Begonia ‘Princess of Hanover’ (Rex Cultorum Group)

‘Princess of Hanover’ in the Rex Cultorum Group

Within the Rex Cultorum Group, ‘Princess of Hanover’ is maintained as an individual cultivated clone recognised by large olive-and-silver blades. The principal wild background comes from Begonia rex, native to shaded, humid rocky places in the eastern Himalaya and is the group’s principal wild ancestor.

Further tropical rhizomatous species expanded the cultivated lineage, and repeated selection fixed combinations such as large olive-and-silver blades with red backs in named clones. ‘Princess of Hanover’ exists only in cultivation. Propagation from the named plant preserves large olive-and-silver blades, large olive-and-silver blades with red backs and its established growth habit.

How to care for Begonia ‘Princess of Hanover’ (Rex Cultorum Group)

Light

Place Begonia ‘Princess of Hanover’ (Rex Cultorum Group) at an east window. A south or west window also works from 0.5–1.5 m back, provided hot sun does not reach the leaves. An overheated window is too intense once metallic and pale zones bleach first, followed by dry brown margins. In a shaded shelf position, the petioles elongate, the crown leans and new leaves are smaller with flatter colour contrast. Use the newest mature leaf as the light check. Healthy leaves naturally show the olive-green and silver upper-surface pattern. Give enough light for firm compact growth, but do not use hot sun in an attempt to strengthen the pattern.

Watering

Water Begonia ‘Princess of Hanover’ (Rex Cultorum Group) when roughly the upper 2–3 cm has dried and the lower shallow root zone still holds a trace of moisture. Rewet the entire root ball in one pass, allow full drainage and keep the drainage hole clear. Small sips leave dry pockets behind. Repeated complete drying weakens the feeder roots even when the thick rhizome still looks firm. The surface may look dry while wet mix remains trapped under the rhizome, where oxygen is most limited. Check directly beneath the rhizome of ‘Princess of Hanover’. Surface colour alone does not show moisture around the fine roots. A plant making leaves under useful light uses water faster than one paused in a cool, dim position.

Substrate and roots

Begonia ‘Princess of Hanover’ (Rex Cultorum Group) has a broad surface rhizome and a relatively small mat of fine roots beneath it. If using ready-made houseplant mix, adapt it to give the same structure as a fine, open foliage mix containing peat-free substrate or coir plus small bark and pumice. Avoid both compact fine compost and bark-only mixes: the first stays airless, the second leaves dry gaps. Keep the container broad and close-fitting, with the rhizome resting above the mix. Keep ‘Princess of Hanover’ at its current depth and use the pot for stability; tightly packed mix restricts air around the roots.

Temperature

Keep Begonia ‘Princess of Hanover’ (Rex Cultorum Group) at 18–26 °C, with 13 °C as a cautious indoor minimum. Keep both foliage and pot away from night-time glass chill and air-conditioning outlets. Keep the plant in a stable position away from radiator heat and cold window glass.

Humidity and airflow

Household humidity can be enough. Raise it towards 55–70% only if new leaves repeatedly open with crisp edges. Leave open space around ‘Princess of Hanover’ so overlapping leaves do not form a damp, still pocket. Fresh air matters most after watering, cleaning or while a new leaf is opening.

Fertilising

Feed Begonia ‘Princess of Hanover’ (Rex Cultorum Group) with a balanced complete fertiliser at quarter strength every four to six weeks while it is actively making leaves or shoots. Reduce the dose when light falls, the pot stays wet longer or fresh potting mix already contains fertiliser. Keep the solution dilute and allow complete drainage so fertiliser salts do not collect around the roots. A stronger formula will not improve the olive-green and silver leaves. Maintain steady growth; excessive feeding produces soft leaves that damage easily.

Repotting

Repot Begonia ‘Princess of Hanover’ (Rex Cultorum Group) when the rhizome reaches or circles the rim, roots fill the shallow pot, watering becomes uneven or the mix loses its open structure. Choose a pot only 2–3 cm wider. A fine Begonia root system performs best without a large volume of unused substrate. Avoid bare-rooting. Each section kept after division must have fine roots and at least one sound growing point. Continue feeding only while temperature, light and active growth support normal nutrient use. Use the extra width to give the newest growth on ‘Princess of Hanover’ room, while the rhizome remains on the surface.

Support, pruning, handling and leaf care

Let Begonia ‘Princess of Hanover’ (Rex Cultorum Group) form a broad foliage crown over a surface-running rhizome. Turn the growing end into free pot space, and divide only a rooted piece that retains a bud and healthy leaf. Keep the light direction steady while a leaf unfolds, then make any small rotation once it is firm. Support the olive-and-silver leaves of Begonia ‘Princess of Hanover’ with an open palm during cleaning. Use a soft damp cloth once, ; repeated polishing can mark the blade. Snip damaged or spent growth with a clean tool and keep cuts clear of wet substrate.

Signs of stress in Begonia ‘Princess of Hanover’ (Rex Cultorum Group)

A folded olive-and-silver spiral

The central coil is normal, but the blade should continue expanding and remain firm. Remove a leaf if its folded centre stays wet or develops soft brown tissue. Several hard, bronzed coils need a close check for broad mites.

Silver areas turn papery brown

Scorch usually forms a dry patch on the exposed side. Move the plant to filtered light and keep the remaining healthy tissue. Water-soaked damage spreading across both olive and silver areas should be removed.

Irregular dark patches on red leaf backs

Red colouring beneath the blade is normal when it remains firm and even. A local area that becomes translucent, wet-looking or soft indicates damage. Remove an expanding lesion and follow its petiole to the rhizome.

Large spiral leaves collapse after repotting

Fine-root damage can cause temporary droop, and an oversized wet pot can quickly damage the shallow rhizome. Inspect a persistently heavy pot, remove soft roots or stem tissue and place the healthy rhizome in fresh, airy mix in a small pot.

‘Princess of Hanover’ and curious cats or dogs

‘Princess of Hanover’, including its large olive-and-silver blades, contains soluble calcium oxalates and is toxic to cats and dogs. A pet that chews the leaves or a stem may drool or vomit; underground portions contain the strongest concentration. Keep the pot beyond a pet’s reach. Collect removed leaves and block access to exposed roots or crown pieces during repotting. Recheck access after moving furniture or placing the pot on a lower surface. If drooling, vomiting or swallowing follows contact with the leaves or a stem, contact a veterinarian. Bag discarded roots, spent substrate and cuttings after repotting, then wash hands.

A royal-style name with a long garden life

‘Princess of Hanover’ is an old-style commemorative cultivar name, using the title associated with the royal house of Hanover. The intended princess has not been identified.

The cultivar belongs to the Rex Cultorum Group and has received the Royal Horticultural Society’s Award of Garden Merit. Its “rex” background ultimately recalls the Latin word for king.