Amarillo Gold
Rudbeckia
Rudbeckia irsuta, Rudbeckia irta, Black-eyed Susan
Scientific classification
Class
Dicotyledons
Division
Angiospermae
Family
Asteraceae or Compositae
Order
Asterales
Genus
Rudbeckia
Species
hirta
Key information
Description
Biennial ornamental herb up to 45 cm tall, suitable for full sun exposition, with upright habit and very vigorous growth. Ideal for landscape use, either in isolated groups or in compositions with other ornamentals, to form brightly coloured borders in warm shades, also perfect in planters and large tubs. Flowering takes the form of a profusion of daisy-like flowers, grouped in the typical flower head inflorescence that distinguishes the Rudbeckia genus , which are well liked by useful insects such as butterflies and bumblebees.
Variety description
It has large, bright yellow flowers with a very attractive lime green centre. It can also be grown in summer with several plants in large pots. In landscape use, rudbeckia amarillo gold with its large flowers (6.5 cm) can be arranged either in isolated groups or mixed with other blooms to form brightly coloured borders. Also excellent in large tubs to create bright yellow patches, thanks to the light green flower centre (as opposed to the dark centre of r. Toto). It is an ideal species for summer cultivation in greenhouses and early transplanting is not recommended when temperatures are not permanently above 13°c. However, it is a flowering for full sun or partial shade exposures. In the greenhouse, the use of high-dose phytoregulators is recommended from the third week of cultivation onwards to keep the plant compact and well trained.
Origin and history
Curiosities and special features
The generic term, Rudbeckia, was given to it by C. Linnaeus in honour of his predecessors, the Swedish botanists father and son Rudbeck; the species name, hirta, refers to the down on the leaves and stems. Some varieties are also used as cut flowers for fresh arrangements and bouquets as well as in herbalism.
Origin and distribution
Native to North America, it was nicknamed 'Black-eyed Susan' by the first British settlers who, when they arrived in the New World, were fascinated by its flowers with golden daisy-like petals and dark flower heads; introduced to Europe in the late 17th century as an ornamental plant, it is now naturalised in many European areas where the wild species can also grow wild below the mountain belt.
Main features
Flower size
Large-floweredvarieties.
Leaf
The Leaf blade is oval.
Flowering period
Flowering lasts from late spring to late summer for between 120 and 140 days, allowing us to enjoy its inflorescences in gardens and terraces during warmer periods.
Inflorescence
Inflorescence head, typical of Species belonging to the botanical Family Asteraceae.
Leaf colour
Solid colours.
Plant height
The height of the plant varies from 0.35 to 0.45 m, making it ideal both for creating isolated, homogenous, monochrome groups and for mixed compositions with other ornamental plants of different lengths in order to create sinuous movements and landscape perspective views.
Lifespan
Biennialherb.
Where to plant
Best used as bedding plants , outdoor tubs, borders, large pots, planters
Stem
The stem is herbaceous and covered with thick hair; the variety has no thorns.
Flower
The flower is daisy-shaped, large, with a dialipetal corolla and plain petals. It is arranged in large flower head inflorescences. It flowers from late spring to late summer, with a flowering period of between 120 and 140 days. It is attractive to bees, butterflies and bumblebees.
Growth
It has a very vigorous Growth becoming one of the most prevalent blooms in the garden, a focal point of significant ornamental value.
Plant habit
Erect in habit of growth, it creates fantastic perspective effects in Composition with other ornamental Species of different heights.
Branching
The development of the plant is realised with Medium branching of the aerial part.
Growing conditions
PH
The optimal pH of the soil or medium for rudbeckia is sub-acidic, between 5.8 and 6.2.
Soil preparation
Before transplanting in late spring, carry out light digging removing any weeds, previous crop residues and bulky stones. Continue by burying slow-release organic or chemical fertiliser and break up coarser clods to obtain greater softness and improve fertiliser distribution. To improve drainage of excess water, preventing damaging water stagnation, create a raised bed by lightly ballasting. Finally, add professional substrate for flowering plants to the surface by approx. 5/10 cm and carefully level out.
Read more on the Joyflo blogSun exposure
It expresses its best vegetative development in half shade, full sun; if possible, expose the plant to maximum light for optimum flowering while ensuring it is watered in proportion to its needs.
Ideal climate and temperature
The biological temperature is between 8 and 32 °C. The ideal temperature is between 16 and 20 °C. It is well adapted to hot summer climates.
Use
The prevalent use is in the following areas:
Floral arrangement area: dried and fresh flowers Outdoor ornamental field Landscaping
Hardiness
Variety of medium hardiness, tolerates summer heat well.
Soil
The ideal soil is what is known as medium-textured soil, in which sand, clay and silt are balanced to achieve adequate porosity and proper drainage; for use in tubs or planters, a substrate for spring plants based on fibrous peat and perlite, which is light and well draining, is recommended.
Difficulty
Its cultivation is moderately difficult, requiring an overall average level of management; following the correct cultivation instructions regarding exposure, irrigation and fertilisation will lead to excellent growth and flowering results.
Growing tips
For best performance in a flowerbed or pot, consider the following cultivation conditions:
With little light the plants will not flower Expose the plant to maximum light Keep the substrate dry at low temperatures
Combinations with other plants
Flower-bed compositions with other ornamentals such as Begonia semperflorens, Calluna vulgaris, Ipomea x hybrida, Lobularia maritima, Lobularia x hybrida, Petunia grandiflora, Salvia farinacea, Solenostemon, Tagetes patula, according to polychromatic combinations, are of great decorative effect.
Care and plant health
Planting
For bed planting we recommend an average density of 18 plants per square metre to ensure the correct development of each specimen, thus obtaining a proportionate and compact final composition that best expresses the aesthetic value of the plant with its spring-summer blooms. We suggest placing each seedling on a raised bed with the collar outside the soil surface, taking care not to damage the roots and avoiding completely sinking the root balls, which must be well moistened; finally, water immediately after planting, preferably during the morning hours.
Pruning
Remove the dried Flower with scissors or remove it manually by detaching it at the peduncle insertion on the stem.
Propagation
It can be multiplied by root cuttings or by seed.
Watering
Use rainwater, or alternatively water from the aqueduct, by hand watering or with an irrigation system. When transplanting, water abundantly for the first time, then take care to allow the soil or substrate to dry slightly between watering, but avoid excessive desiccation and water stress resulting in dry, grey leaf edges. Do not water the aerial part of the plant during the afternoon or evening.
Read more on the Joyflo blogFertilising
During pre-transplant soil preparation, carry out basic fertilisation with organic or slow-release chemical fertiliser. During the spring-summer period, following proper post-transplant settlement, regularly apply a balanced fertiliser suitable for ornamental Species to the soil or medium at the foot of the plant, to be distributed in liquid form, i.e. diluted in the irrigation water, without exceeding the frequency and doses applied.
Read more on the Joyflo blogEdibility and toxicity
Pet safety
Toxicity not known. Avoid administration.
Edibility for humans
Inedible.
Toxicity for humans
Toxicity not known. Avoid ingestion.
Expert advice
Tip
In landscape use Rudbeckia Amarillo gold can be used either in isolated groups or mixed with other blooms (white blue red) to form lively borders with long-lasting blooms until mid to late summer. In warmer areas it is best to place it where shade or half-shade shelters it during the central hours of the day.
Profile curated by Maurizio Arbusti.




