Tulipa tarda 'Interaction' is a stunning cultivar with variegated foliage and yellow flowers with white edges.

Tulipa 'Lucca' is a unique multi-flowering tulip with lemon yellow flowers with black centres.

Tulipa 'Blushing Apeldoorn' has large, deep yellow flowers blushed and edged with red.

Tulipa 'Ice Cream Banana' has a dense centre of double lemon yellow petals surrounded by pink and green.

Tulipa 'Caribbean Parrot' offers stunning sunset shades with ruffled yellow and cream petals edged in pink and orange.

Tupistra nutans has thick, strap-like, emerald green, evergreen leaves and edible flowers used in curries.

Uvularia grandiflora forms clumps of erect stems with twisted, bright green leaves and pendulous, bell-shaped, yellow flowers.

Uvularia sessilifolia forms spreading colonies of delicate, erect, burgundy-infused stems with pendulous pale yellow flowers.

Veltheimia 'Lemon Flame' is a South African bulb and easy houseplant with shiny foliage topped with torches of greenish yellow tubular flowers.

Verbascum 'Gold Nugget' is a compact mullein with large, bright butter yellow flowers with deep red eyes held on branching candelabras.

Verbascum 'Honey Dijon' is a stocky, compact, vigorous mullein with large peach and gold flowers with plum purple eyes held on branching candelabras.

Viola Celestial 'Twilight' offers impressionistic-looking flowers with rich combination of mauves and golds.

Zantedeschia 'Captain Lido' has yellow and orangy-pink, trumpet-shaped flowers above bright green leaves with white spots.

Zantedeschia 'Millenium Gold' is a spotted calla lily with bright yellow trumpet-shaped flowers with green bases.

Zantedeschia 'Nashville' has yellow and magenta, trumpet-shaped flowers above bright green leaves with white spots.

Zantedeschia 'Summer Fun' has bright yellow trumpet-shaped flowers with green bases and bright green leaves with white spots.

Zanthoxylum piperitum, the Japanese pepper, is an aromatic, spiny shrub with small, yellowish green flowers and scarlet fruits used in Japanese and Korean cooking.

Zanthoxylum simulans, the Sichuan pepper, produces brownish red fruits that have a spicy, numbing effect.

Zanthoxylum simulans, the Sichuan pepper, produces brownish red fruits that have a spicy, numbing effect.

Zephyranthes citrina or citron zephyr or rain lily is an amaryllis relative with beautiful deep yellow flowers.

Zephyranthes primulina is known as yellow zephyr lily or yellow rain lily. It has cute, pale yellow flowers with pink reverses.

Zingiber mioga is the culinary myoga shade ginger from Japan with edible young shoots and yellow flowers.

Zingiber mioga 'Dancing Crane' is a variegated form of this culinary ginger from Japan.