Podcast Summary: Hoy por Hoy (SER Podcast) – "Meterse en un jardín | El pelargonium ‘Bontrosai’, un geranio extraño y oloroso"
Date: November 11, 2025
Host: Àngels Barceló
Guest/Expert: Eduardo Barba

Overview

This episode dives into the fascinating world of rare and aromatic geraniums, focusing specifically on an unusual and captivating variety: the Pelargonium ‘Von Trosai’ (sometimes referenced with slight variations in spelling as "Vontrosai" or "von Troçai"). Landscape gardener and botanical expert Eduardo Barba joins Àngels Barceló for a hands-on, olfactory exploration of plant collecting, botanical naming, plant care, and propagation, interwoven with personal anecdotes and a call from a listener.

Key Discussion Points & Insights

Introducing Plant Guests (00:32–01:19)

• Àngels and Eduardo begin by reminiscing about the abundance of plants on the show’s terrace and today’s focus on a single, special plant.
• A quick nod to the Aglaonema 'Silver Queen' and multi-season chrysanthemums sets the cozy, plant-loving tone.

Difference Between Geraniums and Pelargoniums (01:19–02:46)

• Eduardo clarifies common confusion: The common "geranio" in Spanish gardens is often a pelargonium.
  • "En lo que nosotros normalmente llamamos en jardinería a nivel popular, geranio, en realidad son pelargonios." (01:56 – Eduardo)
• True geraniums (e.g. Geranium Rozanne) and pelargoniums belong to the same family but are different genera.

The Peculiar Pelargonium ‘Von Trosai’ (02:46–08:14)

• Scent and Appearance:

  • Pelargonium ‘Von Trosai’ is described as highly aromatic, with citrus and resinous notes.
  • Leaves are uniquely curled and pompon-shaped, which makes the plant visually striking.
    • "Son hojas en forma de pompón o de moño… se recurva hacia abajo, como si fueran garras... hace tanto rizo que la hoja casi se convierte en una flor." (07:00 – Eduardo)
  • Commonly found in balconies across Spain, especially warmer regions.
  • English nicknames: "lemon sculpture scented geranium," referencing both scent and shape.

• Origin Story:

  • Eduardo discovers the plant in a photo featuring French gardener Gilles Clement, then embarks on a botanical sleuthing journey with friends and colleagues.
  • The variety is rare in nurseries; eventually, Eduardo acquires a specimen through a chain of gardeners from France to Bilbao to Madrid.
    • "Este geranio lleva ya este Pelargonium vonmigo desde junio en la terraza y se ha puesto como una mala bestia." (06:16 – Eduardo)
  • The robust nature of this plant: can grow vigorously, forming multiple 'arms' and reaching over a meter.

Listener Interaction: The Resilient Geranium (08:14–12:08)

• Marina from Zaragoza shares a poignant story: her geranium, a cherished reminder of her grandmother, suddenly lost all its leaves but exploded in blooms during an atypical season.
  • Eduardo explains "stress bloom," triggered by the plant’s production of ethylene—a hormone released under extreme stress that can cause total leaf drop and a last-ditch flowering.
    • "El geranio siente que va a morir y destina absolutamente toda su energía a una última floración." (10:16 – Eduardo)
  • Advice: avoid additional stress (such as pruning); instead, optimize light, water, and environment to help the plant rebalance.
    • "Es como un ser vivo cualquiera, como una persona... muchas veces lo único que hay que hacer es mejorar su condición de entorno." (11:43 – Eduardo)

How to Propagate Pelargonium ‘Von Trosai’ (12:21–17:18)

• Step-by-step propagation using a cutting:

  1. Use washed river sand as the main rooting medium for its porosity—prevents rot while retaining enough moisture.
     • "Lo que nosotros queremos en un esquejado siempre es que el esqueje en la parte baja tenga mucha aireación y una retención de agua justa...” (13:07 – Eduardo)
  2. Prepare a small pot: base of universal substrate, then fill with coarse river sand.
  3. Take a cutting just below a leaf node; remove lower leaves.
  4. Allow the cut surface to dry and form a protective "callus" for 1–2 hours.
     • "Lo que hay que hacer es dejar secar el corte. Porque de esa manera el corte se deshidrata y genera una pequeña película seca, un pequeño callo que evita que los hongos y las bacterias del sustrato penetren en la planta." (15:33–16:10 – Eduardo)
  5. Insert the callused cutting into the sand.
  6. Place in a bright, sunny spot (minimum 3 hours direct sun), and fertilize in spring and autumn.

• Notable advice: Geranium 'Von Trosai' is especially robust, cold tolerant (down to –4ºC), and primarily attractive for its foliage, as the blooms are small and unremarkable.

Final Notes and Fun Facts (17:19–18:09)

• This pelargonium reputedly resists the "mariposa del geranio" (geranium butterfly/pest), making it even more valuable for gardeners.
  • "Este es un geranio que es repelente para ellas y atractivo para nosotros." (17:55–17:59 – Eduardo)
• Eduardo encourages listeners to request Pelargonium ‘Von Trosai’ from specialty nurseries—its unique leaves are worth the extra effort.

Memorable Quotes

• On botanical nomenclature and popular naming:

  • "Le puedo llamar geranio perfectamente, pero a nivel botánico sería una pequeña incorrección. Pero nos da igual porque la jardinería ha de ser popular y. Y eso es lo que nos gusta también." (02:47 – Eduardo)

• On plant vigor:

  • "Tiene cinco o seis patas, como un pulpo vegetal ya de un metro y algo... lo que tienen los Pelargonium graveolens es que tienen un vigor inusitado y como tiene sol, como está, encuentra el sitio." (06:19 – Eduardo)

• The plant’s appearance:

  • "Es rizar el rizo. El refrán este de rizar el rizo, pues aquí este Von Troussai lo cumpliría." (07:00 – Eduardo)
  • "A veces parece un pequeño bonsai." (07:58 – Eduardo)

• On stress blooming:

  • "El geranio siente que va a morir y destina absolutamente toda su energía a una última floración." (10:16 – Eduardo)

• Plant care analogies:

  • "Es como un ser vivo cualquiera, es como un animal, es como una persona... muchas veces lo único que hay que hacer es mejorar su condición de entorno." (11:43 – Eduardo)

• On propagation practice:

  • "Dejar secar el corte. Porque de esa manera el corte se deshidrata y genera una pequeña película seca, un pequeño callo que evita que los hongos y las bacterias del sustrato penetren en la planta." (15:33–16:10 – Eduardo)

Timeline of Important Segments

| Timestamp | Segment | |:-----------:|--------------------------------------------------| | 01:19 | Difference between geranium and pelargonium | | 02:46 | Introduction to Pelargonium ‘Von Trosai’ | | 05:51 | Eduardo’s search and acquisition story | | 07:00 | Unique leaf morphology and aesthetics | | 08:14 | Marina’s listener call and geranium dilemma | | 10:16 | Explanation of 'stress blooming' in geraniums | | 12:21 | Step-by-step pelargonium propagation tutorial | | 17:55 | Pest resistance and summary of plant virtues |

Tone & Atmosphere

The conversation is lively, passionate, accessible, and filled with botanical delight. Àngels brings warmth and curiosity, Eduardo provides deep horticultural expertise with a sense of wonder and philosophy. The segment bridges the gap between technical plant care and the genuine emotion plants inspire.

For Listeners Who Missed It

This episode is a must for plant lovers, urban gardeners, and anyone fascinated by the interplay of scent, memory, and botany. By the end, listeners will better understand what makes Pelargonium ‘Von Trosai’ so special—and perhaps be inspired to start their own rare plant hunt or propagation adventure.