My next guess was another tea rose, 'Double Delight', bred by Swim and Ellis and introduced by Armstrong in 1977. This description sounded much more like it, as it noted the good scent. Yet the rose in the picture looked much too red. My grandmother's rose was very creamy with ruby accents.
Then came the epiphany. The experts said this rose was unusual as it changed colour according to how much sun it got. In full sun it becomes quite red, but at lower light levels, it stays cream. That explained it. Granny's rose was growing in her side garden in dappled shade and my detective's nose closed in. The final piece in the puzzle was the rose's scent. It was rated one of the top 10 scented roses bred since the 1960s, by the All American Rose Selection (AARS).
This was a rose from which you drank in the scent - it was almost lemony and intoxicating. So, my conclusion was that my grandmother's rose is the hybrid tea 'Double Delight'.
The book describes it as being susceptible to mildew, so perhaps this variety is not ideal in Auckland's and Northland's humid climates, but it is worth growing further south for its scent and its clever ability to change colour.
To improve lankier roses like Double Delight, some growers suggest planting three roses of the same type in a clump together, to give the illusion the rose is bushier than it is.
You get more roses out of the deal and won't feel like you're spoiling your garden by picking all the prize blooms for a vase.
When feeding roses, you want to encourage blooms over foliage, so well balanced nutrition, high in potash and organic matter is a good bet. Sheep pellets are suitable, as is basalt rock dust and a sprinkle of blood and bone or liquid fish fertiliser, plus a thick pea straw mulch to retain moisture.
Hygiene is important with roses to avoid perpetuating the dreaded black spot. Remove any fallen leaves and prunings (and don't add to the compost heap). If you keep your soil covered with mulch, there is less likelihood of mould spores splashing on to foliage when watering.
A good vintage: petal landing pads for bees
* Go for species of roses, or old rose cultivars, which aren't too heavily petalled if you wish to encourage bees in your garden. David Austen English roses may look old, but were bred in the 1960s and 70s and are heavily petalled.
* Don't appreciate roses' prickles? Go for a banksia rose. These strong climbing roses have tiny flowers covering long thornless stems.
* Try spraying rose foliage with a mix of baking soda, Neem oil and a drop of detergent to reduce mildew and aphids, or spray with liquid seaweed solution for general health and disease resistance.
* I asked rose expert Marg Thompson for her top five vintage rose picks. She said: 'Francis Dubreuil' (1894), a fragrant blackish-red tea rose; 'Jean Ducher' (1873), a soft, salmon-pink tea rose; 'Souvenir de la Malmaison' (1843), a pale pink classic; 'Souvenir De Madame Leonie Viennot', a large climber with two flushes of pink and peach flowers; and the yellow 'Lady Hillingdon' (1910). They are all well scented.
* Choose a rose which has large, colourful rose hips as a feature in autumn, such as the old rugosas. They are also known for their prickles. Rosehips are also high in vitamin C and make a lovely tea. Marg's fifth equal contenders were 'Fru Dagmar Hastrup' (1914), 'Alba' and 'Blanc double de Coubert' (1892), which are lovely rugosa cultivars. They are also more resistant to disease in humid climates.
* This column is dedicated to the memory of my wonderful Granny who died earlier this month. Her roses will grow on.
